Every map has alternative routes, whether there is a track laid or not. You have a vehicle that can fly, jump, rotate, and drive on anything, so there's no reason to limit yourself to using just a track.

That said if you're looking for multiple guided routes, then many maps have branching tracks although some of them are hidden. For example, the official map Corruption has a teleporter behind a bunch of buildings. Many other well-designed maps use this same kind of concept, but nonetheless here are some maps with branching tracks:
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=567503440
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=422423352
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=675489000
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=546105655
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=455344967
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=464441384
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=518641023

I'm well aware that some maps have hidden things in them. What I was looking for was maps like Striker (or maybe another I don't recall). That moment when I was on a wall with another just in front of me I thought "Hey that could be fun on split screen, like I'm on the wall on the left and the other on the right, face to face". That's the king of things I was looking for.
Anyway those maps looks really nice, thank you !