I recreated this issue, because the original was marked a a duplicate. This is NOT the case. The original ticket: MC-191094. The fake duplicate ticket: MC-190258. The fake duplicate points out the high ram usage while my original tickets points out that in the 1.16 release candidate server the server ram usage will grow exponentially. With this I mean that when the server is idle the server ram usage will keep growing and after around 50mb drop 50mb back again. This is visible in the server window. These are not stats gotten from task manager or something.
"Growing exponentially" does not mean going up and down the same amount constantly, if it stays about the same, it is intentional, RAM usage can fluctuate like that.