Having a low energy and high energy track in the same OST is really good! I think a lot of people fall into the trap that an OST has to sound all the same but variety is super important!
I love the way it flows into the surfing track and the really fast background notes add a lot to the overall composition! I think 1 thing I might have added was a bass drum of some kind when the snare really picks up in the second half of the surfing track as the low end can feel a tad empty there to me.
Great job!