Don’t delete any files. That is not the point. It is probably the entire MSFS package including aircraft, liveries, gauges, base scenery, all the objects and object textures. Eventually, when you’ve deleted all the MSFS files, there will be no more stuttering because there won’t be any MSFS left. If you’ve deleted any files, you might have to reinstall MSFS.
I have no idea what is causing the stuttering. I’m not making ANY changes until after a fix is delivered.