I know it sounds obvious but, are macros that make you just hold a button to make u perfect dash allowed? cause I saw a submitted run (can't remember which one but probably in the top 10) and the runner just hold "S" and perfect dash so I thought it was a macro.

Generally, a macro is 1 key that presses multiple keys in a certain timing thing. This generally is not allowed in speedrunning, as it can interfere with the showcasing of a players skill.

For example, a macro could be 1 key pressed and it clears an entire room.

The only thing speedrunners generally allow is rebinding; having 1 button do 1 keypress, but I believe you can do that from within the game :P