This behaviour was not observed before.
My environment is Windows 11 Pro Build 22557.1.
I removed and installed the Supernotes app again, but the result was the same.
When I first opened the app after reinstallation, it was accessed to my account without a login procedure, but after that, when I turned off and turned on the app again, I asked for login again.
Thank you for being so concerned in advance!
I have also been experiencing this behaviour however, I have observed it for a few weeks now.
My environment is Windows 11 Pro Build 22000.493.
I noticed that after exiting the application, Supernotes is still being run as a background process.
When I manually end the task(s) and relaunch Supernotes, I am automatically signed in and the load time is significantly reduced.
This is not an ideal workaround but a temporary fix that seems to be working for me.
I hope this can aid in the investigation 
Thanks for these reports, we will look into this and get it fixed as soon as we can reproduce it as that sounds quite annoying!