Pilar,
The reason none of the payment options are working properly is because the order information is not being passed to the payment processor. The fact that it affected all of the payment plugins was a clue that it wasn't the payment plugin itself, rather something that would affect all of them. I checked the database and while I am sure there could be more than just these two tables affected - the following tables have additional fields that were added from the VM to J2 migration component (from the Joomla 3 site). The reason it still works in J3 is due to the newer database parameters in Joomla 4/5 and since those fields are still using older J3 database settings (which are not set to NULL), the orders are not saving since there's an extra field in the table that is not saving anything at all.
The following fields in the two tables I looked into need to be removed first on your end in order to continue testing...
#__j2store_orders (order_vm_id)
#__j2store_orderitems (vm_orderitem_id)
on my test server, I can see the order is now saving correctly in the database (after removing those two fields) however the order amount is still not properly passing so most likely there are other affected tables. If you can send me the J3 extension that converts from Virtuemart to J2 - I can use that to see what other tables are affected as well.
Adam