On the other hand…
When speaking Czech, people still call me Jennifer. Why should Czechs be called something different when speaking English?
I'll grant you Bořivoj/Boris and some other rare examples, but for the most part, if your name is Marek, Honza, Libor, Marketa, Jana, etc., it's easy enough to pronounce in English, and if you want, you can say „Hi, my name's Jana, it's the Czech equivalent of Jane.“ I always told my teenage students to be proud of their names and not to bow to the „anglification“ of everything. (Same with Czech accents, but that's a whole other can of worms.)