Blades In The Dark

I think one of main issues is that Runeterra (world of Arcane and League of Legends) has fantastic races like Yordles, while Blades is humans only game.

There's nothing in Blades that requires you to run it in Doskvol, but that setting does have a few things going for it that makes Blades easier to run. Firstly, the players can't just nope out of the city and lie low for a while in the countryside. They're forced to deal with Doskvol all the time. Secondly, there are real and immediate consequences to murder and death. This incentivizes the players to at least attempt non-lethal methods. Of these, only the pressure cooker environment is really crucial for a game of Blades. The rest of the setting adapts just fine. You could, for example, run Blades in a post-nuclear war 1950s era New Orleans where the surrounding lands are surrounded by nuclear fallout. The city, however, survives due to protections conferred by devils.

Doskvol is just a tad too dark for Arcane, I do agree there. You don't necessarily have to adapt Blades itself tho. Have you taken a look at a|state RPG? It also uses the Forged in the Dark engine but is a little more lighthearted. In that game, the crew are troublemakers trying to make one corner of a hellish urban landscape into a better place. The system makes caring as important as fighting. I think you might have better success with that system.

I haven't seen Arcane, but tweaking the setting should be relatively straightforward.

The key thing about Doskvol that I'd recommend carrying over is the pressure cooker environment you get from having a place that the crew can't easily or meaningfully leave. It allows the tension and stakes to naturally ratchet up over time, forcing the crew to deal with the problems they create rather than laying low until things blow over.

Aside from that, ghosts and the occult could get narrative makeovers to better suit your setting.

I think you should go for it!