onenote keeps asking me to sign in over and over

If clearing the saved logins doesn't stick, check the clock. Settings > Time & language > Date & time, make sure set time automatically is on. A PC clock that's off by a few minutes breaks the sign-in tokens and gives you this exact loop. After that, a Quick Repair of Office from Settings > Apps > Installed apps > Microsoft 365 > Modify.

Usually a stale saved credential. Close all the Office apps, open Credential Manager > Windows Credentials and remove anything mentioning Microsoft Office or OneNote, then sign in again once. Is there a work or school account under Settings > Accounts > Access work or school? An old one there often fights with your personal login and causes exactly this loop.