What about SimpleX Chat? Comes without identifiers, is open source and not located in the US. Relay Servers are located in Germany, UK and Sweden and it's possible to host your own. Last audit was in 2024. No metadata is stored. Fundings are handled very transparently and presentated on the Website.
Not meaning to advertise it, just genuine interested in other peoples opinion.
I'm using Tuta and their app for a few years now. The app was slow indeed but it's good now, no problems so far. Lack of IMAP support is justified with security, they say. I personaly don't need IMAP as I'm completely satisfied with the app, which is available officially in f-droid btw.