Culture victories are not difficult imo, AIs are rarely focused on winning the game.
So usually you have plenty time for your cultural. Diplo skills are important, many AIs cannot declare war at pleased, with such neighbours you can live in peace.
Conquest & Domi are harder on continent type maps, when you need Astro for Galleons along with your other units.
Deity is very often about using opportunity windows for units like Cannons, Cuirs, Cavs, also needing Galleons hurts

Pangaea types are considered easier.
Diplo are easiest, if familiar with mechanics.
Space should be easier than conquest & domi, as you can avoid fighting the strongest AI(s).