I’ve heard of crazy Reliquaries games winning much earlier than you normally get a culture victory, especially with leaders that have bonuses to early game tourism (Magnificence Catherine, Ludwig).
The idea is to generate so much early game tourism that you win before other civs unlock the Enlightenment civic. I’ve never done that before, so I decided to try it with Ludwig. I played on Deity but turned on extra game modes to make it easier - Barbarian Clans, Secret Societies, Heroes & Legends. (Monopolies and Corporations is basically cheating for culture victories, so I left that one out.) Pangea map to make it easier to meet everyone so I could start earning tourism from them sooner. I restarted a couple of times until I got a good start, and the first city-state I found was Kandy; my first governor title went to Amani to become suzerain there. It still took until turn 157 on standard speed to win, and it took national parks and rock bands to finish things out - I was earning over 1000 tourism per turn by the end of the game. Fairly normal for a culture victory, nothing like a rush.

It seems like a lot of things went right in that game. I got a religion with Reliquaries, I was suzerain of Kandy, I got Voidsingers for the extra great work slots, and the game settings were heavily tweaked in my favor. It still wasn’t enough to win in the early game instead of the late game. What else needs to go right to get a culture victory without those late-game bonuses?