I came here with the exact same issue. Disabling and re-enabling BT doesn't help with my Samsung S20 FE 5G. The only thing that seems to help is if I restart my phone. Sometimes it works for 2-3 days, but this morning I had to restart the phone, and now, maybe 10 hours later, it still won't unlock the doors for me. If I use NFC or the button ion the app, I can unlock the car, and even the music would play while the car still won't recognise the phone key unless I restart the phone.
I have tried everything I could think of, including not ever letting the Tesla app go to sleep, but nothing seems to help.