Don't have to be - fintechs like Revolut, Wise, N26 are based in different countries, but service customers in a decent chunk of Europe.
and you can get debanked from all of them in the same incident.
The "incident" has to be pretty severe for you to be debanked in multiple EU+UK countries. Little less than terrorism would do it (I was going to say coup attempt might, but the Catalan leaders who tried to illegally secede from Spain didn't get debanked, so probably not).