Slow patch changes

I have been using Mainstage for live gigging for about 2 years now with good results. It is pretty heavily loaded with Ivory Grand Pianos, Omnisphere with Keyscape, Kontakt 5. Audio interface is Focusrite Scarlett 18i20. I am using a Panorama P6 and an old Korg N1 as midi controllers.

For the last few months I have been noticing slow patch changes, even on relatively simple concerts that don’t use resource hogs like Keyscape. It is not such a big deal between songs, but is a real problem for quick patch changes within a song.

Since I have been using it for quite a while, I have lots of old Concerts in my Mainstage folder, but I didn’t think that would cause overall slowness. Do I need to do some house-cleaning to speed things up again? I remember seeing posts recommending to delete the Preferences file. I am not sure where to find that file, or how much work it would be to put things back the way I want them.

Has anyone else had a problem with patch changes getting sluggish over time?