I can’t compare it to the cad examples but meshmixer is definitely easier to use for small stl edits than blender, especially for things like cutting and keying parts. If you are just trying to make a pin smaller or hole larger, editing the xyz of specific points in blender may be easier depending on shape. Good luck!

I was in a simiar boat, but once I started learning it really took off and I couldn’t find enough things to model/fix! I started with meshmixer, it’s pretty simplified but still somewhat powerful and I think Windows only. Once I found stuff I couldn’t do with it I switched to blender and now I’m much faster with it. I found there are some things each implements better so if having an issue I’ll switch and try something else. I highly recommend picking one and watching youtube videos specific to what you want to change in a model

Edit: you may be able to get by on some of the connectors by lowering flow too, depends on how dialed in your printer is, everyone needs different tolerances