By “excess”, I mean the difference between your c. 115 Gb and my < 29Gb. You should be able to get a similar size to what I have, and still retain all the instruments, plug-ins and other components.
You might benefit from deleting everything in the root Library Steinberg folders, and then reinstalling from the Steinberg Download Assistant.
You’ll see that the sizes indicated here are nowhere near 91Gb. Dorico’s guitar samples are in HALion Sonic Selection; and you’ll need the HALion Sonic Instrument to play them.
You can delete the older Sonic 3 VSTs and standalone app, too.
As to the user library: you will certainly want to keep all your preference files, options, and other similar config files, but have a look around and see what’s causing that 26Gb of data. Check the Auto-Save folder. Have you saved any Endpoints, or Playback templates?
You might benefit from using an app like OmniDiskSweeper, which sorts the folders on your disk by size, allowing you to see what’s using up all the space.