I've had the S20 FE for a little while and it worked fine for about 2 weeks. Then it became incredibly buggy and nothing I do fixes it. Essentially once I plug my headphones in and move with my phone music will start playing, then it will skip, it will pause then start again, it will open the phone app and call people. Its impossible to use and infuriating to deal with. The only time it MIGHT work is if my phone is completely still, however that is also touch and go on if it will work.
Before anyone suggests: I am restarted my phone, uninstalled and reinstalled the app, made sure my settings allowed it to play in the background, made sure my battery wasn't optimising the app. I have exhausted all options.
Just as a process of elimination can you remove any relevant sd card.
First please put the phone in Safe Mode which disables your downloaded app's but let's your stock app's keep working. If the issues stop then this highlights a downloaded app as the possible issue. Come out of Safe Mode and start deleting your most recent downloaded app's one at a time until it stops.
Clear your phone's System Cache Files by turning your phone Off and then from a set series of button presses go into the phone's System Files and clear the cache. No information is lost this way.
Have you considered having it swapped out within any relevant Cooling Off Period @salmfish
If your past that period then consider a factory reset after backing up and removing any relevant sd card.
And a Samsung Experience Store or Samsung Service Centre can take a look.