There is a way to do it, but it’s not the most typical way MacOS users do it for everything else, which involves Right Click->Open With->Other->Always Open With. Xcode’s file associations are super aggressive.
I believe that “Get Info”->”Open With”->”Change All…” still works, and there are command line methods or third party tools.
>>nerdsn+(OP)
select in finder the file that currently opens with XCode, then press Cmd+i. It opens the information panel. There in the Open with section, you can chose the app and then also Change all to not use XCode.
>>dwaite+2c
Something is different. Right Click->Open With->Other->Always Open With 100% did not have any effect when I needed it in the past. Not sure what current behavior is. This was a huge thing for me.
>>nerdsn+2z
I have noticed something similar. I feel like I have done that so many times for XML files. Perhaps it is re-establishing the settings when any kind of update gets installed.