How could we make a minecraft server lag?

Here I have been asking myself the question for a while and I would like to know a little so I ask it here .. Can someone tell me?

I mean depending on what minecraft version if it's 1.16.3 ur gonna be wanting quite a decent amount of ram prob 4/5gbs
for 1.7 to 1.12.2 u can prob get off with like 1 or even 2gbs

If you need help setting one up just search on youtube

Minecraft how to make a minecraft [version] server