Just to put things into perspective I'm simultaneously running two Daggerheart games right now for two groups with no one else in common - and for those who don't know Daggerheart there are 18 playable ancestries in the core rules, and the world's presented are half a dozen pages of guidelines and a blank map for people to add locations to at the start and going forward.
Two simultaneous campaigns. Five regular players in one, four in the other (plus one guest in each). And we're about fifteen sessions into one campaign and eleven into the other. And between the two campaigns every single regular's ancestry or their culture except one has been deeply important to them and to the campaign. (I can only think of one character between the two campaigns both has mattered for - and the "except one" is a social gamer and deeply invested enough to have created the STL for and 3d printed a model of the party mascot, and not from pre-existing parts). The lore has a huge effect on the campaign not despite but because of how little extraneous lore we started with show much we've been able to build. And I have never got or even seen such investment in their own individual parts of the setting by using something pre-fabricated outside the table and campaign.
And no I'm not a "Service DM". Last night I had three out of four players literally squirming in their seats at different times and two out of four for different events tell me "I should have seen that coming"; all of them had a blast and the most any had played with me before this campaign was a game of Crash Pandas. And I've been able to do that by building on and twisting what the players brought and are deeply invested in because it's theirs as much as mine.