This mod disable cooldowns, bring back the classic swing hand animation, still works with shields.
This mod is really simple to use, it works on server, on multiplayer game.
The mod is available on Curseforge : https://www.curseforge.com/minecraft/mc-mods/old-combat-mod
I don't it know if it's useful but this mod can be good for old players, or just if you don't like the way of PVE/PVP.
An example :