OK, who can recommend a domain name registrar that:

- Is boring and dependable and has a rock solid track record
- Has a really good UI, including on mobile
- Supports as many TLDs as possible
- Isn't likely to get acquired by someone else
- Ideally supports multiple payment methods as insurance against accidental card expiry

I'd settled on Google Domains... but they just sold themselves to Squarespace! https://9to5google.com/2023/06/15/google-domains-squarespace/

Google Domains shutting down, assets sold and being migrated to Squarespace

Google Domains is "winding down following a transition period," with Squarespace taking over the business and assets...

9to5Google
@simon All of my domains are registered with gandi.net ; it hits your stable and unlikely to be sold criteria, as well as the multiple ways to pay as a backup. The UI is better than most. My colleague loves porkbun.com-- better user experience for sure, but I cannot personally attest to its longevity.
@simon ..... aaaaand I just found out that gandi is not so stable a business as it has been. Sigh. I'll stop recommending it for a bit until I am sure of it again myself