I’m going to assume you’re trolling. Most spammers don’t use OP_RETURN because they get a 75% discount if they embed their spam using SegWit. OP_RETURN is about VC-backed spammers who want to “comply” with the “mainstream BTC standards” so their investors don’t get spooked. E.g. Citrea that is VC-backed by Lopp.

You’re asking two different questions. OP_Return doesn’t bloat the UTXO set, but it definitely results in more data added to the disk as a result of relaxing the filter.