Minecraft mod for server monitoring?

Is there a mod for MC with which the server load (RAM consumption, etc.) can be read out or monitored and in the best case also recorded?

Should be compatible with Forge version 1.12.2

Probably not, because a mod is intended for the player and a plug-in for the server.
Where is the player supposed to get the load on the server from, it is mostly not public.
If it is your own server, there are enough tools to read the load externally, i.e. Not in Minecraft.

Mods are of course also for the server

What tools are there?

Install a web panel with a resource monitor for your server.

What is there for example

No they are not.
There are plugins on the server, they are not mods.

But plugins only change the properties of the blocks, mods add new blocks