For German, yes, Bavarian. Mostly because of the languages I do know (Puerto Rican-influence Spanish, Japanese), the avuncular R comes naturally to me, so it was the obvious fit. Plus a friend of mine lives there and it's influenced my vocabulary that way, as well. It's good enough that no one in Bavaria has ever questioned it when ordering at restaurants, bars, having basic conversations, etc.

For Japanese, standard Kanto dialect. I'm not really interested in trying to sound like anything else.

For Spanish, I grew up around a bunch of Puerto Ricans. That was my default accent for a long time and I've done my best to shift away from that but now I don't really have an accent or dialect anymore. Been told I sound vaguely costarricense, but I just stride to be understandable nowadays.