I'll agree that one of the things that has struck me as peculiar in League of Legends compared to most other games is how disconnected the lore feels from the gameplay. Usually lore in a game serves to create meaningful context for a player's decisions, but I don't even really get how the constant battles on Summoner's Rift fit into the metaplot, how champions who are sworn rivals have no trouble fighting on the same team, why fierce-looking jungle monsters are totally passive until someone attempts to kill them, what minions are beyond pinatas full of gold & XP, etc, etc.
In short, nothing that happens in the game itself makes any sense to me in the context of the lore and it's better for my suspension of disbelief to ignore all of it the moment I leave the champion select. It makes League of Legends feel like a spinoff combat game pulling its setting and characters from other established franchises, similar to Heroes of the Storm or Smash Bros. Or sometimes it kind of feels like Riot has an in-house staff of fanfic writers on the company payroll. It's weird.
Don't get me wrong, I think the vast majority of the lore is of exceptional quality, and that is probably at least partially due to it being completely unconstrained from having to compromise its excellence to serve the gameplay (and same goes vice versa). Also, narrative is just one of the many elements that strike me as strangely untethered to League's overall experience (others are where skins fit into this, the game's eSport focus while adopting the visuals & terminology of RPGs, and... well... don't even get me started about how emotes are expected to be used to express anything about the game itself beyond "that was good" and "that was bad").
However, as much as this frees each individual design element to reach its full potential, this also results in an entertainment product whose whole isn't really any better than the sum of its parts. It's like how a movie soundtrack needs to support and be supported by the visuals and story but even if (or especially if) it's excellent in its own right but incongruous to the other elements it distracts and ultimately detracts from the full movie experience.
Or, to use maybe a more apt metaphor, the various aspects of League of Legends remind me of a team of champions who each are trying to solo carry the game alone rather than cooperate on a shared strategy.