Newbie question about tagging

I just signed up for a trial but am hesitant about pulling the string so am looking for some reassurance. I searched and found a couple of near misses on this but want to ask for clarification because of previous bad experiences with other products. My family has a large shared library of music and audio books, about 75,000 files stored on a NAS. We’ve used iTunes to manage our stuff since inception. We’ve developed an idiosyncratic system of tagging to help us sort and search using the “Comments” and “Genre” categories in iTunes and have customized the metadata incrementally. Some time ago I tried to change to another media management program and it replaced all the custom tagging with generic info. Fortunately I was able to restore from backup, but it was traumatic. I want to make sure that if I don’t fall in love with Roon in the next two weeks I can revert back to the current state painlessly. Any advice would be appreciated.

Roon doesn’t change your underlying metadata, so nothing to worry about.

Use the “Watched Folders” feature (in Settings->Storage) to add the folder containing your files. Roon will not disturb your files in any way unless you explicitly ask Roon to delete them.