I think the trick with CVs is that its the easiest victory condition to both "be good at", and also "not possible to win".
Here's what I mean. I've had Tall CV games that were a breeze. Generally its a situation where you have one major culture player in the game. In that situation, you can focus all of your great musician bombs at them at them, and probably optimized, you will generate about 70% of your total tourism through this method. With even a bit of optimization you can wreck the competition and win faster than any other condition.
But then there are scenarios that are extremely difficult for CV. You get 2 major culture players (or god forbid 3). Now you have to spread the load around to convert everyone, and things become significantly harder. Of course the boredom numbers are a big wildcard, sometimes you get like 20% more tourism because of boredom, sometimes its 0%. In those scenarios, the only real viable way to win CV is to beat down one of your cultural opponents, and then focus your tourism on the other one.
This is why I find Tall CV brittle on Immortal+. When things are good, they are really good, and I will just win like its no big deal. But if things start going sideways, I often don't have the military to project the force I need to correct the issue. The best thing you can try to do is go autocracy (with the CV tenants in the tree), and utilize the military powers there to compensate for your weaker base supply and production.