Other options which MAY or may NOT work include bringing all your troops home or getting out of democracy to republic. Communism takes a little adjusting to, as finances are the pits in that government. War weariness can be a little fickle in democracy or republic, and predicting what will work is problematic, just as in reality.
I would have done something about the war way before I got to 70% entertainment. Such as focusing on obtaining (capturing) more luxuries, ...
How you can predictably make peace with everyone at the same time, I have NO idea. I have read of the potential for giving a lot in return for peace, but haven't given a whole lot in practice. If you have been at war with some civs for an extended period, you may have become a 'mortal enemy,' which does not bode well for an extended peace.
Sometimes the bleepin' game can turn into very painful learning experiences.

If things continue to go badly, it may serve to change your objectives for playing this one (like learning from it instead of enjoying it).