I really like 16D, 11D, 1D, and 20A. I'm not sure about some of the tenses for anagrinds; for instance, "go to war" seems like it should be "going to war" (I know that doesn't grammatically work with the surface) and I don't know if I parsed 3A right, but if it's dropping the last two letters of DECADE[-nt], I don't know if "mostly" is specific enough. That said, those are small nits on an entertaining puzzle; looking forward to solving more! :)
Yeah I kinda rushed through making this puzzle, so a few ungrammatical anagrinds crept in (10A, 6D, 15D). As for 3A, that is the right parsing; I think I have seen some clues with that kind of indicator, but yeah probably it would’ve been better to find something more specific. Thanks for the feedback though, glad you enjoyed!
One of my favorite current constructors offered some advice I've taken to heart on indicators, which is that they shouldn't be ambiguous. "Mostly" tends to mean that you're deleting the last letter. Some might ALSO use it to suggest that you're deleting the last two (or even the last three, in a longer word), but the more you stretch the sense, the less satisfying it is as an indicator.
Here, for instance, you might have gone with something like [Corrupt without Bible for ten years (6)]—not that that's a better surface, just that it's a more specific deletion.