Thanks for the very clear description.
The problem from the users side of view is that the BSQ wallet is an integral part of Bisq. There’s no known external BSQ wallet apart from Bisq (correct me, if I’m wrong).
From the user’s point of view, exporting payment accounts serves as a kind of backup. So a user would expect that he could use the backed up payment account with whatever new installment of Bisq.
I think Bisq software should either
a) backup full BSQ wallet recovery information
b) warn on import, that an imported BSQ account can not be used to receive BSQ with the new wallet
edit: c) force creation of a new BSQ account and block the old one from active use