Disabling Exchange Password Required notification

Related to this question/thread that is now closed: https://discussions.apple.com/thread/251202049 - I can't get rid of (suppress, remove, disable, configure) this system level notification.

On my work Windows laptop I need a VPN to connect to the office network, but this isn't the case with my personal iMac (which I use for 99% of my work stuff). I previously had no issues accessing my work mail, calendar etc via macOS internet account management.

This week, I was forced to change my password. I did this on my Windows machine, re-signed in to everything on that device and my iOS devices (which do have a management profile installed), and continued working on my iMac (I can still access Outlook, Intranet etc with no issues).

But now the system service is asking for the new password. I have updated it via the "internet accounts" settings screen (as well as confirmed the 2FA), this seems to work, but the login state isn't being held on to somewhere and the notification persists. I have also manually entered the password in the Mail preferences, but it fails to verify. I've also tried the suggestion from the other thread, where you turn off "automatically manage connection settings", but still no luck.

I've logged a call with our own IT department, but they're obviously not really interested ... and will likely just tell me that as it's on a personal/unsupported device they can't/won't do anything. My only current option is to make the whole account on the iMac inactive - this kills the permanent notification, but also means I lose access to having my work mail, calendar, etc sync on this device.