Apple and Google both provide support for offline speech-to-text using local models. Users can configure it to be fully offline.

The Murena Voice to Text service in /e/OS sends the user's audio to OpenAI which is hidden away in their terms of service:

https://community.e.foundation/t/voice-to-text-feature-using-open-ai/70509

Voice to Text feature using Open AI

Thank you a lot for your positive and supporting comments about our new /e/OS Voice-to-text! Regarding its implementation in /e/OS, I’d like to explain a few things to explain why we have chosen an OpenAI STT API to implement it and how it’s going to evolve in the future: What we have learned from our experimentations with STT models that run locally on the smartphone for speech recognition: they work quite poorly, they make a lot of mistakes in voice recognition they are not able to mix la...

/e/OS community
/e/OS is heavily marketed as private but in reality it has enormous privacy issues like this with their default apps and services. It's also heavily marketed as avoiding Google services but yet has privileged integration for Google services and connects to multiple by default.
/e/OS doesn't keep up with basic privacy or security patches for the OS or browser engine used not only for the default browser but also the WebView used by many apps including email clients and far more for rendering web-based content. For more info see https://discuss.grapheneos.org/d/24134-devices-lacking-standard-privacysecurity-patches-and-protections-arent-private.
Devices lacking standard privacy/security patches and protections aren't private - GrapheneOS Discussion Forum

GrapheneOS discussion forum

GrapheneOS Discussion Forum
/e/OS is not a threat to mass surveillance but rather significantly helps with it by making exploiting devices to extract data or take remote control over them far easier. They do not keep up with basic High and Critical severity patches. All devices sold by Murena are insecure.
Even on Pixels, /e/OS is extremely far behind on providing the current High and Critical severity privacy and security patches due to being so far behind on OS updates. They mislead users by setting a fake security patch level and changing the UI to mask what's happening.
Murena is a for-profit company and /e/OS is very clearly built and managed for the benefit of Murena. Despite this, /e/OS receives a huge amount of EU government funding. If you're an EU taxpayer, your money is being used to build this extraordinarily insecure and non-private OS.
@GrapheneOS false !
@s94 /e/OS is receiving millions of dollars in EU government funding. /e/OS is built and managed for the benefit of Murena, a for-profit company. /e/OS has the same leadership as Murena. What about this do you think is false?
@GrapheneOS Murena allows Ungoogled Android and open source to be democratized and accessible for everyone. It's maybe not perfect, but they have good intention and you can't disrespect them like that.

@s94 No, Murena is scamming people at a large scale for profit. They're pretending to provide a private OS which is in reality not at all private. We've explained how it lacks the most basic privacy and security. It even sends sensitive user data to OpenAI without informing users, which is far worse than how Apple and Google are handling speech-to-text from a privacy perspective.

Contrary to their marketing, it gives extensive privileged access to Google services and always connects to them.

@s94 Murena do not have good intentions. They're a for-profit company selling people fake privacy products and services. What they care about is money. They've set things up in a way that they can get a bunch of government funding to build the product as if it's a non-profit in order to sell that from their for-profit company.

What they're providing is much worse than people simply using an iPhone. It's worse than using stock Android on a device receiving monthly backports or OS updates...

@GrapheneOS Euh ... Grapheneos you put put a shame on yourself reaction like this. There is /e/Os, calyxos, lineageos, etc. Everybody can choose for themself. Thuis looks a bit like the Linux distro war. Thatcher distro better, that distro gets money. Focus on yourself and stop creating posts like this. It will not bring you a step further and it is just negative energy.
@richarddebruin We're providing accurate information in response to /e/OS spending years spreading misinformation to mislead people about GrapheneOS. Other groups have done that too. This has caused substantial harm to our project and our team. In particular, the fabricated stories about our team and personal attacks such as baselessly claiming our founder is crazy and delusional have heavily contributed to harassment. The founder of /e/OS and Murena has directly participated in that too.
@richarddebruin We've responded to GrapheneOS and our team being heavily lied about with accurate and verifiable information. Many people have been helped and steered away from using highly insecure and non-private products because of what we've posted. There are many responses saying so. What we posted improved privacy and security for people who are now going to make a better choice. Not everyone realizes that those operating systems reduce rather than improving privacy and security.
@GrapheneOS @richarddebruin motherfucker your OS only run on google pixel devices and you're punching down those who supports fairphone and many others ? REALLY ? You élitist bitch, did you audit the SOCs on pixel devices? You'd better

@defred @richarddebruin /e/OS and Murena are scammers causing substantial harm to people through selling them extraordinarily insecure and non-private devices. It's a blatant grift for profit, not a serious attempt to provide people with better privacy or security. They do the opposite of that.

We currently support every device meeting the very reasonable requirements listed at https://grapheneos.org/faq#future-devices. The purpose of GrapheneOS is providing people with privacy, not scamming them like /e/OS.

GrapheneOS Frequently Asked Questions

Answers to frequently asked questions about GrapheneOS.

GrapheneOS
@defred @richarddebruin We're not willing to have insecure devices unable to protect people's privacy and security in order to expand usage share of GrapheneOS and get more donations. Instead, we're working with an OEM to have their devices meeting our requirements. Broad device support is directly counter to providing privacy and security. Selling devices not being provided with basic privacy and security patches including end-of-life devices as a privacy product is blatantly scamming them.
@GrapheneOS @richarddebruin yet you can't guarantee that either.
@defred @richarddebruin /e/OS does not provide basic Android and Chromium privacy/security patches without huge delays while misleading users about it. They outright fail to ship huge portions of the patches for many months or even years. They substantially roll back the standard privacy/security model and features too. They aren't doing the bare minimum to protect user privacy and security. They're streaming's people microphone audio to OpenAI without telling them beyond a Terms of Use...
@defred @GrapheneOS @richarddebruin “lets be afraid about a backdoor in the Hardware of Pixels with no evidence supporting that claim other than FUD and prefer the phone with an open frontdoor, no roof and smashed windows”🙄😭
@imnobody @GrapheneOS @richarddebruin FUD ? google, just sayin', wait and see...

@defred @imnobody @richarddebruin /e/OS is streaming user's microphone audio to OpenAI without telling them when they use speech-to-text. Meanwhile, Apple and Google at least support doing it locally.

/e/OS is misleading users about the many missing privacy and security patches including setting a false Android security patch level and changing the user interface to downplay it. What's that if not having backdoors?

/e/OS has repeatedly covered up their security weaknesses and vulnerabilities.