Big Sur Keychain Access: No Passwords

I just received my new 2020 MPB running Big Sur and transferred everything directly using Migration Assistant. However, none - not one - of my stored passwords transferred across. Only certificates and keys. I can tell because a) I cannot see any passwords in the Keychain Access app, and b) when I attempt to log on to a web site or app where the password is stored - for example, my Adobe account - I am not prompted to select the password (as I was on OS X Catalina).

A few other comments:

• Yes I can still see the passwords in my old MBP 2019.
• Yes I can still see the passwords in my iOS devices.
• I tried exporting the Keychains from my MBP 2019 then imported manually into Keychain access on my MBP 2020 running Big Sur, but no change.
• I note that the UI of KeyChain Access is completely different and does not seem to have an 'iCloud' section. See screenshots.

Also: in OS X, passwords were indicated using the "@" symbol, but these are not showing up in Keychain Access on Big Sur.