For example, the Research Table, I would like to prevent that from spawning anywhere on the map.

use betterloot and remove it from the items list

wtf betterloot?!  I think you need something like https://umod.org/plugins/anti-entity mudpill

Both methods will work depends on the current loot plugin for the owner and what they want.

Both are good ways to do it and correct though.

Chop Chop