Yes, perhaps / I guess so, too . Nevertheless, what I have posted above is valid for any case – IMO.
Kind of... I agree with your way of proceeding by the way, but looks like OP is interested in appearing a Portuguese tax resident to the Portuguese bank, so that Romania is not informed about his account through CRS, but without actually being a Portuguese tax resident, so that he doesn't have to pay Portuguese tax either.
There are ways to achieve this but I won't recommend any of them, legal tax avoidance is surely the way to go... I would just do what you suggested in your first sentences (inform the Portuguese bank about being a tax resident of Romania and deal with CRS information, especially since the amount is relatively small and tax/fines in Romania are low), or just leave Romania to a country where one can legally live tax-free.