Fix low TPS and lag

TPS is ticks per second and it should sit at 20. Below 20 the world runs in slow motion for everyone. It is a CPU problem, not a network one — players seeing rubber-banding with good ping are looking at low TPS.

1. 1Run /tps in-game or check the graph in the panel to confirm the drop is real.
2. 2Install Spark and run /spark profiler start, play normally for two minutes, then /spark profiler stop.
3. 3Open the report link. It names the plugin, mod or chunk that is taking the time.
4. 4Fix the top offender before touching anything else — one bad plugin usually accounts for most of it.

If nothing stands out, the usual culprits are view-distance set too high, thousands of entities in a farm, or a hopper array. Lower simulation-distance first — it costs the least in gameplay terms.