try this

create a second free account and the password can sit there on your server at rest syncing without MFA. Then you share that folder with full rights to your main account. It just works and you can see it all under "Shared with me". You can even edit/delete.

Not ideal but hey it works. You are limited to 2Gig but until Proton fixes this what can we do?

I have multiple accounts for this, one per machine I want to sync. Unfortunately you cannot use a proton-alias or hide my address alias to create an account.

I was looking for something like this myself.

Maybe a similar example would the the Vault folder in One Drive.