Big Sur Deleted emails not going into trash (fix didn't work)

I have exactly the same issue as posed in this discussion. It started immediately after installation of Big Sur:

https://discussions.apple.com/thread/252427617

My deleted emails disappear. My settings are exactly same as OP:

I checked my Account preferences and the 'Move deleted messages to the

Trash mailbox' is checked. I have the Erase Deleted Messages set to One

Month. I changed both of these settings and put them back... thinking

that the actual setting was not being saved... and my emails are still

not going to trash.

I tried the solution from @mingoslkd :

let's try creating an 'All Trash' mailbox

I can create the All Trash mailbox, but nothing goes into there either. Any suggestions?