Can't help you with manor specifically, but i can tell you how i used to insane times when i was parkour addicted:
1. Complete map ton of times till you can do it with closed eyes(just reflexive).
2. Once you complete step 1, study each jump of map on its own and see if you can take a shortcut even if its 0.5 sec, if you find one then train it til it's easy.
3. Once you have schematic for perfect run, keep trying thousands of times till you make it.
4. As manor is enourmous map make sure to make breaks and keep your chill or you will just get worse.