After migrating my account to my Microsoft log-in, I now have to enter my password and 2FA each time I start the launcher. This doesn't happen on Windows 10, so I am guessing it is in fact a bug. I have checked for a "Stay Logged In" Checkbox, which isn't present.
Thank you for your report!
We're tracking this issue in MCL-18924, so this ticket is being resolved and linked as a duplicate.
If you would like to add a vote and any extra information to the main ticket it would be appreciated.
If you haven't already, you might like to make use of the search feature to see if the issue has already been mentioned.
Quick Links:
π Bug Tracker Guidelines β π¬ Community Support β π§ Mojang Support
π Project Summary β βοΈ Feedback and Suggestions β π Game Wiki