how do i find out why my game is running slow and sluggishly?

whats this best way to find out why its moving slow and sluggish?

and is there a way to find out if the issue is with my computer or with the scripts and load in game itself?

Use a built-in profiler. You’ve got to go to menu bar → Window → Profiler. In profiler window you can see what takes up memory, CPU usage etc.
Hope this helps!