It is a minefield

Thank you:) I write a lot of emails to religious organizations (US-American), I study them and they always sign with "God bless" or "in him" or something like that - than I don't know what to do (I am not religious...), so I sign with Best regards, but this seems to be weird... also greetings from Germany is strange, isn't it...
It is very complicated and I prefer the German formal way.