Bonus: while your every access to porn is being logged for the state, they can log your VPN use too just in case there is anything relevant for law enforcement to care about.
Past options that don't work anymore include SNI inspection (replaced with ESNI/ECH, but wasn't hard to circumvent; say you want good.com when you're doing SNI, say you want evil.com when sending a Host: header), and DNS blocks (but now DNS-over-HTTPS is a thing, so as difficult to control at the state level; would require a court to compel in-state DNS-over-HTTPS providers to publish fake facts, which violates federal law; but irrelevant because AWS, Cloudflare, and Google don't have any assets of value in Utah).
I'd say it's basically impossible to ban VPNs. If it happens, you'll see random VPN employees detained/arrested while on vacation or something like that, unless the news cycle blows over. China can do it, because they can just kill tech execs that won't cooperate, but we typically don't do that in the US.
The VPN provider knows the user is in Utah and connecting to Pornhub, so there might be an argument for knowingly facilitating circumvention. No clue if that's something that they can prosecute, though. I'd be de-nexussing Utah were I running a VPN company.