If you’re looking into removing the Universal Search app from your DSM, because it’s bogging up your NAS, you can do it using root permissions via terminal.
Just log in via SSH and issue:
synopkg uninstall SynoFinder
In case you just want to stop it, then you’ll need to issue
synoservice --disable pkgctl-SynoFinder
You can add this script to Task Scheduler so that it is issued on every restart.