UTXOs don't have anything to do with Bitcoin decentralization which is from programming, BIP contributions and consensus, Bitcoin hashrate distributions as well as Bitcoin node distributions.
That's not 100% correct. A bigger UTXO set does increase the cost of validation for nodes, and thus full nodes would be cheaper to run. (@crwth: indeed the set is partly stored in RAM, so it increases RAM requirements; but it's also stored on disk, it however must be fastly accessible so a SSD is a must for that).
However, the OP_RETURN increase just wanted to target that problem. OP_RETURN outputs do NOT create new UTXOs because they can be safely ignored by the nodes, i.e. they're not added to the UTXO set.
There are techniques to store data in the blockchain, like Bitcoin Stamps' "fake public key" approach, but also the Ordinals technique, which create UTXOs that will never get spent. This approach was cheaper as using OP_RETURN until Core 30's increase, because you could fit more data in a single transaction than OP_RETURN's 80 bytes.
The idea behind Core 30's OP_RETURN increase is to eliminate the cost difference, and so make it attractive for NFT fanbois (who can't be stopped, see below) to switch from "fake public keys" to OP_RETURN which is the least harmful method to store data (and OP_RETURN data can perhaps be permanently deleted in the future by most nodes).
Core 30's OP_RETURN increase doesn't create any new incentives for storing data, so it neither is a valid reason for an UTXO set increase, nor does it create a new "cheap" method to store data. Other methods are still cheaper.
Now BIP 110 aims to ban some of the harmful UTXO set increasing storage techniques in addition to ban big OP_RETURN data outputs. The problem is that the filters can be circunvented, as it was
recently shown by Martin Habovštiak. And there's also
this method which cannot be banned by any upgrade because it uses vulnerable "fake" private keys (!).
So the BIP 110 filtering approach only creates new problems (de facto confiscated coins) and doesn't solve any old problems.