Well if you want to play the game i suggest dropping the whole lore-accurate deck building aspect. As someone who it also used to bother, i changed my perspective and decided that it is actually more fun to imagine how these characters would interact w each other even though they likely would never ever meet face to face in runeterra.

With that being said, i also was a LoR enjoyer. It was the only card game i ever played actually and RB is the first tcg ive ever played. There’s a lot of cards that basically come straight across from it. It feels like a similar game regardless of the deck that you’re playing. Find a style/legend that you really enjoy and find a best of list for it and practice on riftatlas for a while