Starsector 0.97a is out! (02/02/24); New blog post: Simulator Enhancements (03/13/24)
You could try to reduce the battle size in the options, so less ships fight at once. Yet they (can) enter as reinforcements when other ships are destroyed. Not Sure if that helps though.
You could further tune it down in the ini file in the starsector folder. Maybe a lower resolution below your native one if you havent tried.