>>55323328>they have basically no level designYes they do, the constant dive spots that lead you to areas covered by large rocks and individual remote islands ARE the level design. You're meant to explore it. It's just all completely optional so unless you're a completionist you're not going to bother.
>up to level 35 ones, which is like 10 levels higher than you will be when you get surf, and those will appear even if you set a repel because of thatfirst off, You get Surf after beating Norman, that's gym 5, and the main water routes (meaning the biggest ones that are absolutely neccessary to beat the game) don't start until after Lilycove. That's Gym 6, by that point you should be over level 35. Theres only one surf spot that's required prior to this and that's going from Mauville to Route 118 which is an incredibly small patch of water.