Ram Usage slowly increases during idle.

At startup my ram, 64gigs DDR4 4000mhz, is at 13%
After 4 hours it's at 30%
Another 4 hours it's at 60%
I reboot, it's back down to 13% and again slowly increases usage.

Nothing is up and running, it's mainly just up as a Plex server.
SFC /SCANNOW finds no issues
CHKDSK finds no errors
Malwarebytes, SuperAntiSpyware, and Malwarebytes anti-rootkit all show up clean.

I checked Task Manager for anything using that absurd amount of memory and don't see any programs eating it up.

Maybe it's just Windows managing unused RAM. Another shot in the dark is some memory leak somewhere (a driver maybe?).

Use the Task Manager, sort the Memory column.

Take a screen shot at say 30 min/1 hour intervals.

Have you tried with Plex uninstalled to see if it is the cause?
Is the PC occasionally fully shutdown to flush out the RAM ?

"for just simply idling...." I have to assume you are either joking or a troll.

From your screenshots, you obviously have a ton of useless Apps, stuff running in background and no attention to Windows and Application settings.

No, that's just idling. I turn it on in the morning, go to work for 9 hours, come back and it's around 35%