No, I'm talking about the size of the blockchain. It grows at a constant pace of about 2MB per block. Blocks with a lot of inscriptions can get over 3MB, but a hard cap per consensus is 4MB - you literally can't grow faster, regardless how many monkeys you stuff into a block.

There is no such data structure in the blockchain as "UTXO set". What "UTXO set" is, is a subset of the entire blockchain. It's an artificial construct, effectively a database index, that Bitcoin Core uses as a solution to a particular problem (that some transactions need to be more accessible to the program than others). Other implementations might do it differently (e.g. store UTXOs and STXOs separately).

If this solution is no longer capable of solving the problem, that's where the developers' time should be spent.