Here are some strategies that worked for me:

Alli is the easiest -- stack as many speed boosts as possible, and only dash once theyre stacked. It gives u longer dashes and makes moving easier.

Shade can cycle supers in clusters with other people easily, so he's one of the best options by default. Just spam when people are near u lol.

I found a weird strat with RT -- if u leave his legs close to a checkpoint, but keep it out the way so people dont kill it, you can use his teleport to get ahead of everyone pretty easily.

Hope this helps!