The parkour contains jumps that players on easy will find tough. You need to cater to the difficulty, and 4 block jumps are not catering to an easy difficulty.
The theme is incredibly similar to that of a map already on the server, Skyblock Medium (Ironically made by me), which also uses the overworld-nether-end theme. Due to the similarities, I have to contrast the maps to see how your map works with the theme, and due to a lack of real detail, your map does not use the theme well enough.
Some advice -
If you want to use a theme like dimensions, add structures, make it feel like we are actually travelling in the nether or the end, not just on one type of block that is stereotypical to said dimension.
Remember to check that the theme you are using is not being used on parkourse, or if it is, make sure you can match the map already on the server and surpass it in terms of nerve, charisma, uniqueness and ta- Wait... Just Uniqueness...
Remember you can always submit more parkour maps another time.