If you still have access to the old Bisq instance you can do the following:
On your NEW Bisq instance Go to DAO > BSQ wallet > Receive Funds and copy the BSQ receive address shown.
On your OLD Bisq instance Go to DAO > BSQ wallet > Send Funds and paste the BSQ receive address shown in your NEW wallet. Also select the amount of BSQ you want to transfer. You can see the amount you have at the top of the screen.
Make your OLD Bisq instance has enough BTC to cover miner fees. Likely a few thousand sats will be required.
Check the BSQ address matches and then press ‘Send’
On your NEW Bisq instance Go to DAO > BSQ wallet > Transactions and you will see when the BSQ arrives and is confirmed.
NB: in my Bisq parent directory I switched between the new and old directory by changing the name (I added underscore ( _ ) to the dormant directory and set the active directory to the native directory name (Bisq).