Rhyl. Dire hovel. They have tried to improve it but there is just nothing there.
When we used to go when the kids were little, there was a decent fair with roller coasters, a big sun centre, a big exotic butterfly centre, about 10 arcades, donkey rides, a sea life centre, and multiple dozens of shops. Also a lovely, long, wide, spacious seafront.
Now the seafront has been built up with an ugly ass concrete barrier that's about 12 feet high, (because of previous flooding from the sea in that area,) so you can't see the sea at all in Rhyl unless you walk for ages to get around the bloody huge barriers.
Most of the shops have closed - or are closing - and all the nice quirky/unusual shops have gone. Very few places to go or things to do. Maybe one arcade, and a couple of cafe and restaurants, You'd struggle to entertain yourself for more than 2 hours there.
Agree that Blackpool is a shithole, but it's a better place to go than Rhyl because there's so much to do there, and 100s of shops... Also 3 piers, a huge fair, theatres, lots of arcades and pubs and clubs and eateries, and attractions like The Waxworks and The Sea Life Centre and The Tower. And a big beach of course. You could easily spend a week there. Need plenty of money for it all though!