I think you can also ask in their own forum, since in many cases it's their engineers that send patches to OpenWrt for device support.
Anyways, GL.inet has a github repo where they publish their fork of OpenWrt, and the AX1800 is not yet there.
From the latest commits it seems they only recently added code for the B2200 https://www.gl-inet.com/products/gl-b2200/
a product released six months ago or so.