OK, got a bit deeper into this. The configuration is, as someone else said, pretty much like the Capsman config. I went to the Wireless Table and looked into Radios to see whats supported. Upon this I built Channels and Configuration.
The standard 2.4GHz and 5GHz radio has 2 Tx and 2 Rx Chains with 20/40MHz band width. The "stronger" 5GHz radio has 4 Tx and 4 Rx Chains with 20/40/80/160MHz band width. No channel frequency set as I tried to let the AP choose this. I configured the channels like this:
Then over to configurations. For the standard 2.4GHz and 5GHz I did use the same SSID and let the client choose what to use. I did set Tx and Rx chains to be sure it would use them. Specified the above created channels in the Channel tabs and also pointed out the security. This ended up in one SSID using both 2.4GHz and 5GHz, let the AP select frequencies. The SSID name
MikroTik Audience 2x2 was just an idea for the use of 2x2 chains. Then a third config for the stronger 5GHz radio with proper chain/channel/security config:
I created 2 different security. One for the 2x2 SSID and one for the 4x4 SSID. The idea here was to let the family use the 2x2 for their devices such as phone, tablets, laptops etc. along with household products as washing machine, drying machine etc. and the I would use the 4x4 myself got get more bandwith as the 2x2 gets a bit limited leaving room for me
I did use WPA2-PSK and WPA3-PSK with CCMP, GCMP, CCMP256, GCMP256 on both.
Finally I just pointed out the 3 configurations to wifi1, wifi2, wifi3.
I did fire up a virtual machine quickly with Ubuntu server and installed iPerf to test the bandwith of the internal LAN as I only have 250/250 on WAN. Here's the result on 2x2:
And 4x4:
Is there anything I can change or tweak to get out more speed or is this already at its very best?
EDIT: I also updated to ROS 7.2rc4.