Install a NeoForge 21.8.11 ( MC 1.21.8 ) server through the Control Panel (Servers → Select your server → Game servers → Add Game Server → NeoForge 21.8.11 ( MC 1.21.8 ))
So far, no lagging. I have had quite a few mods! It was also easy to figure out how to manage through Scalacube as a first-time purchaser and manage one.