Plex Console shows errors [Notify] Failed to add watch for "<path>" (28: No space left on device)

Yes.

The Linux default is only 8192.

If you can run a count (use FileStation → Properties) and obtain the sum of all the monitored directories, we can increase the table size to accommodate this.

For the benefit of anyone else who finds this:

If you have media in the Plex share, please move it out now.
It doesn’t belong there.
I created the share to hold metadata because the default location afforded by Synology was too small. It was also originally hidden. I made it visible to allow retrieval of log files and database repairs when PMS won’t start correctly.

I am considering a change which will remove the restriction but, for now, I do need to keep no media there. ( I did post warnings in 6 languages)