This is all I can find:

fcp.co/forum/search?query=snapshot%20lim...2/2022&childforums=1

joema mentions that each library, event, project, dup project, and snapshot have their own SQLite database. He also mentions something like 10k clips per database, but that it depends on HW, drive space, and other factors...

Hope this helps.

I seem to recall @joema posting guidance about a limit on the number of snapshots in a library but I can't seem to find the post. Did I imagine it?