Slow internal traffic on RouterOS

Hello everyone!
This is my first time using RouterOS and I’m quite liking it.
I have got 2 rooms full of computer, 1 room for the staff and wifi. All have different subnetworks. I also got a 30mb internet that is NAT-ed to all network. The main purpose with the different subnetwork is to eliminate other networks to ping/interact with another networks, so i blocked those traffics from the firewall. All the networks now can ping within its own network, no other. The problem starts where i want to reach my server. The server is also in different subnetwork, but everyone can reach it. Whenever I try to copy something to it, i only got 3-4Mb/s with gigabit connection, cat6 cables. I read in this forum that the CPU cant keep up with the traffic so i opened up system monitor while copying, and got 15%-20%. After this, i heard that fasttrack connection can solve it. I have got 30mb/s now, still not 1000mb/s, but i lost all of my queue-s to the internet (each room got a queue to the internet of 5-10mb/s except wifi).
My question is, what am I doing wrong?
How can I maximise internal (LAN) speed while queuing the WAN traffic?
I attached a picture to a better understanding

Network:
Got 2 servers, one is at 10.0.1.0 and other is 10.5.1.0.
Also got 4 networks for clients at
10.1.1.0
10.2.1.0
10.3.1.0
10.4.1.0 (wifi)

Thank you in advance for any information!

Isn’t that a switch? If you want to route between the networks you should have a router instead of the switch… Try notrack for communication with the server from other inner networks.

That’s a router. It is a CRS326-24G-2S+. Can you please explain the notrack function?

It is a switch.
https://mikrotik.com/product/CRS326-24G-2SplusRM#fndtn-testresults
Notrack:
https://wiki.mikrotik.com/wiki/Manual:IP/Firewall/Raw#Properties