Update: I played with this a bit recently the issue is the gasket/o-ring is slightly too large of a diameter. I didn't have a smaller one so tried sanding it down slightly which helped a bit. As it ships the fit is so tight that is removes the lube completely so after a single closing & opening it is basically dry again. I use this as a purge valve on my pump not in a fermentor - so my use-case is different and it being so tight is likely preferable in the typical intended use.

It doesn’t require much lubricant. You’ll notice the need for lube when it becomes difficult to turn.

I'm not sure but guessing a lot. I actually have a lot of difficulty turning the plunger even with a good amount on there. Seems like a very tight fit.