Two free Fabric server tools:

• LagLens shows which chunks and mobs are killing your TPS, then lets you click to teleport there. Modrinth
• CapLimit caps hoppers and mobs per chunk to stop lag, with an in-game GUI and no YAML editing. Modrinth

Support development: https://patreon.com/123black

More free mods and guides: https://blacksgit.github.io