SQM works by interfaces not IP addresses. So first you'd have to have separate interfaces for each port. On a device with a switch create a separate VLAN in the switch for each port then software bridge them back into the LAN network. Exactly how to do this depends on the hardware model.
Then you can set a QOS instance on each one, e.g. eth0.3 would be port 3.
You can do micromanagement on the bandwidth allocated to each device with luci-app-nft-qos
So if you keep the same devices connected to each port, you can configure it with that tool.
Your test interface doesn't seem to be in a firewall zone allowed to send traffic to WAN. Simply add it to LAN firewall zone and inform us of the results.
It also appears to not be setup with IPs, etc. I would say use the LAN network and DHCP rules as your guides...you can look from the web GUI, but you can also copy/paste from command line.
What @trendy said that is an old, not powerful CPU and operation at 66 Mb is likely not possible. If your Internet service is faster than about 20 Mb you really need a new router.
In the switch, create three new VLANs. The LAN VLANs could be 1 (existing), 3, 4, and 5, since 2 is the WAN. Set the CPU port "tagged" in every VLAN. Set each of the LAN ports "untagged" in its one VLAN, and "off" in all others. Go to the lan physical settings and add eth0.3 eth0.4, and eth0.5 to the bridge.