But I actually REALLY like the lore behind the game and wish more would be done with it
See, here's where I think the fans are generally incorrect: the game is not obligated to tell you a story and that's by design. It does need to tell you how and why the characters got there and why at this location, but the narrative ends the instant the game literally and figuratively starts. TF2 is the obvious comparison to make, but I think another useful example is fighting games.
Could they do more with the lore? I'm 1 degree of separation from the team behind Arcane, of course they could, but the already existing lore serves its intended purpose and that's all the game has to do.