can ping from the GL-X3000 wifi 192.168.8.0 subnet to the 7590AX 192.168.178.0 subnet,
but cannot ping the other way from the 7590AX wifi subnet to the GL-X3000 subnet.
Your 7590AX will assign a 192.168.170.0/8 IP address to your GL-X3000 when the GL-X3000 connects. You have to use that assigned IP address to ping from your 7590AX. Based on the screenshot you provided, it is 192.168.170.71.
Don’t forget: “repeater” is not “mesh”. Your GL-X3000 will treat the connection to the 7590AX as a WAN connection and the GL-X3000’s firewall will not allow anything on the WAN to connect to the GL-X3000’s LAN (unless you’ve enabled port forwarding or assigned a client as DMZ).
Nahhhh… this might work, but it’s not the way to do it.
Just create a new firewall rule on the X3000 that will allow all incoming traffic from WAN to LAN.
Thanks for posting up the solution and adjustments made. Very helpful for anyone searching instead of folks just getting it fixed and disappearing leaving future readers to wonder whether it worked.