There are no errors in xsession and I don't have a .bash_login or .bash_profile file, so I'm 100% certain neither of those is loaded and thus cancels .profile loading.
When I rename the .profile to .bash_profile and open a new terminal window, it still doesn't load. Everything in the file works (aliases and PATH exports) when I load it manually via ". ~/.profile", but it won't load automatically.
~/.profileis to do so in~/.xsessionrc. See this answer and my comment: https://askubuntu.com/a/1281956. – nyg Mar 19 '21 at 13:12