Anyway or speeding up the process of recreating a roblox model into a cleaner less performance intensive blender model?

I just have had a habit of creating model with a lot of parts on studio, usually parts going over 100 just for a model a size of a hand. Obviously this is not ideal to use for games, however I don’t want to manually recreate the models I have already built by hands. Any suggestions in how to import these models to blender and what methods/workflow should I use to get the models more neat and tidy, reducing as many vertices as possible?