Why's my server so laggy?

first step add a plugin ''clear lagg'' when u press u should see 1.16 is correct so download it and then restart your server when you join do one time /lagg clear

also make people max join 8-12

It could be because the players are very spread out, and you don't have a super high RAM. This is a common issue in aternos. It is the same with BGXCity.aternos.me and ATHSMP.aternos.me. There is really no way you can fix it unless you cut off the world, lol