I’d seriously revaluate the script, running a hundred pawns with physics on does not tax my machine. And I’m nowhere nearly top end specs…
If adding some pawns breaks the performance, you have scripting issues only you can identify. For everything else:
https://docs.unrealengine.com/4.26/en-US/TestingAndOptimization/PerformanceAndProfiling/
It’s a deep dive and there are no easy answers 
Also: