TouchID not filling passwords on Safari and just showing passwords stored inside Safari, not Keychain

I am using BigSur for the first time today, after unboxing a new iMac M1. I migrated all my stuff from an old iMac with Catalina, to this one, using a time machine backup. The new machine is working well but everything related to passwords is a mess. I have been using macOS for 15 years. I have billions of passwords for websites on keychain. Now, on this new machine, when I visit a site that requires username/password, the field username appears filled but when I click on the password field, I am offered the option to unlock the passwords using touchID. This feature fails 100% of the time. If instead of using TouchID I type my mac password I see only the passwords stored inside safari, not those on Keychain. But the keychain passwords are there. Any way to make this work as before?