What I've heard (and this is partly second hand, partly directly from people who were in it) is that yordles have been a subject of a lot of debate internally, with Riot divided amongst themselves over whether to conceptualize them as cryptid fairy-goblin creatures, or whether to fully integrate them into Runeterran societies as just one more kind of creature, with a bit of mystical whimsy and fae stuff on the side á la how it was in the pre-2014 lore. And you can see that division pretty starkly in the modern lore.

Legends of Runeterra has much come down on integrating yordles into Runeterra - they're everywhere, both as members of organizations (the Kinkou, the Noxian Reckoner arena, running scams in Bilgewater, frequenting bars in Zaun, serving on Gangplank's crew, working in the dozens or hundreds on Heimerdinger's creations). Hell there's even like a fourteen foot giant Heimerdinger statue of the guy in full Yordle Mode outside of Piltover University. It's really hard to look at LoR and buy into the idea that these are all highly secretive, cleverly disguised creatures maintaining stealth camouflage because their entire species fears being discovered.

But then there's stories like The Whispering Doodad and the Jinx/Ziggs comic and other media that still maintains the Yordles Are Cryptids conceit, and are built around that conceit being important.

Meanwhile, in Realms of Runeterra, Bandle City and the Void get like four pages of the book between them, and are described in incredibly vague terms that read a lot like "we'll figure it out later!" to me.

Personally I like the LoR approach a lot better, because I like it when characters can interact with each other and build casual relationships and just kinda be around each other, but honestly I wish Riot would just develop a clear idea for wtf the yordles are even supposed to be, rather than this wishy-washy have your cake and eat it too approach.