Yeah, 5G works (I’m on it at the moment!). No issues with MMS, but I haven’t tested RCS since I’m on /e/OS (which doesn’t support RCS as far as I’m aware - I just use SMS/MMS and Matrix). The visual voicemail functionality in the stock /e/OS Phone app doesn’t work with Mint Mobile, but the T-Mobile Visual Voicemail app does work.

Yup! I daily drive a Fairphone 6 with Mint Mobile in the US.

There already is! I had a Furi Labs FLX1 for a while and it was able to run Android apps surprisingly via Andromeda (their fork of Waydroid).

The FLX1 had wireless charging. And a headphone jack. And a replaceable battery… 😔

I’m currently waiting for my Fairphone 6 to arrive, but I believe the sim tray includes a spot for an SD card. I was also recently using a Furi Labs FLX1, which also had an SD card slot. There are other options out there. 😊