Okay, if you were to build a IB deck sure, you could add in nekroz.
The thing is, nekroz have no relation to IB other than name sake. Heck IB barely even relate to each other let alone ritual monsters. Nekroz aren’t even apart of the same archtype as IB, the only relation they have is namesake.
Literally no one is building IB/nekroz because firstly they can’t even be used together, secondly they’re not even considered the same archtype. IB are barely consistent on their own, and combining ritual and synchros aren’t really gonna work out.
Also I don’t think you even know what nekroz are, because they in no way support IB. Heck IB don’t even support IB. Their effects don’t match up with each other, and they could have different names and you wouldn’t even know they’re the same archtype.
Also looking at the cards for IB, 3 of the 5 srs are f2p, whilst the rest are p2p. And there is only 1 ur. So it’s not really that spread out.
That is not to say you can’t play IB the way you want. If you want to run a deck. It’s just unfair to say “I hate how nekroz and IB are spread out” because no one has ever attempted to play those two decks together. If you’ve ever played the TCG it would be like playing ritual beasts and shadows together.