If those countries are in the EU, you have the right to use a bank based in another EU country. The traditional incumbents will likely demand an in-country residential address (in direct contradiction of EU law). Which leaves the internet-only neobanks. I believe the only FOSS-compatible option is Wise, which has a modern web offering and does not even require that you install a native app. I understand N26 does, but it may work with Graphene. By contrast Revolut is a privacy-invading walled garden and should be avoided at all costs.