Security key that's new to me: Thetis Nano-C!
https://thetis.io/products/thetis-nano-c-fido2-security-key-device-passkey-usb-c
Also news to me, I'm clearly behind: FIDO2 has levels:
https://fidoalliance.org/certification/authenticator-certification-levels/
This key is FIDO2 L1, and different applications may require different levels. Notably here, L1 is the minimum to get any certification at all, and you can't get L2 unless you have an actual secure hardware element. So with the device at this level, you get the independence of a separate physical object with a dramatically simpler software surface, but I suspect it might be easier to get secrets right off the key with physical possession.
(Note that this is an organic post, not sponsored in any way. Happened upon it in an eBay listing. I never do solicited or compensated endorsements)