The mod is not working. Also the command does not work

Sorry to inform you that it does work in 1.21.1 fabric. I play on a multiplayer server with Physics Mod Pro, Shaders, and 32-64x resolution resource packs which is equal to a high demanding GPU & RAM setup and I require Memory Sweep on 1.21.1 Minecraft version to efficiently remove memory build up and prevent memory leakage. And I can prove to you that it works whenever you want.