OSIS is absolutely alive, used as the basic format for Sword project. Yes, it is compressed somehow, but the original source codes are freely available on https://gitlab.com/crosswire-bible-society/ and yes, I believe, that from biblical formats, OSIS and USFM (non-XML) are the most often used.

@michal-kay is right, that TEI should theoretically be used, by in fact, it isn’t. It is so complicated, and there are so many different versions of what could be called TEI, that outside of highly abstract academic research I don’t know much about its use in the real life Bible software development.