If you want to spend money, WiFi mesh.
If you want to spend as little money as possible, see if your router can support OpenWRT (The AX73 doesn't, I'd get rid of it if you can and avoid any routers with Broadcom or Qualcomm chips in the future) and then you'll have the Wireless Repeater mode. Use the AX73 as your primary and the openWRT one as the repeater node and you're set.
If Ethernet between the 2 is viable, go with that instead