I’ve been practicing runs and tricks but my pc is too weak to run the game and the timer at the same time. If I can’t get watchable proof video I don’t see a point in trying to upload any run. Also just a side note. Because the pc is weak can I pause the timer through loading zones? It takes awhile to load

If you're running the game on PC, LiveSplit has the load remover you're looking for, and shouldn't cause any framerate issues, as it is very lightweight. A guide on how to set up livesplit can be found here: https://www.speedrun.com/hollowknight/guide/cg9vl

Manually pausing the timer during the run is not allowed, and your run will either be rejected or penalised for the duration you paused.

Assuming OBS as your recording software, make sure you're using the correct settings - depending on your PC's components you may be able to enable Hardware encoding, which is much easier on your system than default Software encoding. You can also try changing your encoder settings - in OBS, there is a field "Encoder Preset", which you can set to Max Performance if you're still unable to play with it recording. Otherwise, you can try decreasing your output resolution, or even the resolution of your game.