Yesyes, Chyros findings are valid .. the Lingbao board has that elevated top metal plate which causes the impression that MX Compatible keycaps are not a great fit on Lingbao's Gateron Blues.
Once you remove that Lingbao top metal plate, you'll see that Corsair, Razer, and all the other MX Compatible keycaps do have a great tight fit on the Lingbao's Gateron Blues; this should be true for original Cherry MX keycaps too. It is the elevated top metal plate which ruins the complete fitment and thus produces that impression of a lose fit.
My FILCO knockoff is not a Lingbao, so there is no top metal plate.