Minecraft server can´t keep up

Hi! Even from the start my minecraft installation have troubles with the hardware (i guess). I have the smaller VPS system, with no players yet.
Over this night the server CPU usage went to 100% even with no players in it, but when i use the TOP command it looks like this and dont undestand why in the web it says 100%:
!58|690x472

I did some tests. This is with just one player flying around and the server is almost 100% for load the chunks (and its ok), but after a 2 minutes quiet the server went again to 30% cpu usage, not 100% like the web monitorization is saying. Check the picture:
!25|690x431

Plugins:
Vault
EssentialsX
EssentialsChatX
GroupManager
PrettySImpleShop
LWC

Even with the ram not exceding the limits, the server cant keep up. This is the java script for check:

java -Xms1G -Xmx2G -jar spigot-1.14.4.jar nogui

Have a nice day!