Minecraft Server Can't Keep Up, No CPU or RAM Usage

Hey there. I start playing SkyFactory 4 with my friends. We have little automatization system (Hopping Bonsai for each tree, packagers for that, and melter for that) And  we start notice a lot of lag. The server is constanting showing "Can't Keep Up" message.

This is a problem that i had with Vanilla minecraft too, when making redstone systems, but not too much. As you can see, even without players, its printing the message "Can't keep up" every 4 seconds and the Avg tick is between 150ms and 600ms. And when players enter to the server, it crash due to 60sec Watchdog killer after random periods of 15min, so in order to make it playable i desactivate Watchdog.

My system is I5-8600K, 16GB RAM, Windows 10, 480GB SSD.

I tried every JVM i encounter, non of them helped me, the forge default seems be the best. I feel strange that even if i allocate 8GB of ram, its never using more than 1.5GB of Memory, never, the garbage collector seems to act instantly to prevent that (can it be causing the lag?)

I tried Allocating only 2Gb, then 3Gb, 4Gb,6Gb,8Gb,10Gb... no difference and always suing no more than 1.5GB

I think of CPU, but no one of my cores surpassed 20%

(screenshot with server running and "cant keep up")

These are my arguments, the default of SkyFactory 4 
-XX:+UseG1GC -Dsun.rmi.dgc.server.gcInterval=2147483646 -XX:+UnlockExperimentalVMOptions -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=32M

I want to remember that this is the same problem i had with Vanilla Server, so the mods are not the problem, but with skyfactory its more noticeable.