"Did you even read the old lore?"

Well, I would tell you to read it only if it's interesting to you, that's logical. I can tell you how I read it. You can start by reading the lores of champions, there's some useful info there as well, not just personal information i.e. some lores reveal about the world or other characters as well. Then you can head over to the Journal of Justice. After that, it's just exploration, you can find many additional details on the LoL Wiki.

I would suggest going to the unofficial wikia and reading some of the older champion's Judgments. They're really phenomenal and offer great insight.

Kick the new lore and take the old lore back.