According to GL.iNet download center the last update was released on 2021-08-03.
Most of the good packages are either not released on this version of OpenWRT or are no longer supported. As an example, modemband for 4g/5g channel aggregation and so on.
I don’t know the reason why production of this model was stopped, because the hardware itself is good, and there is no alternative with two sim cards, but I assume due to low demand.
I would like to upgrade this device to a more current version of OpenWRT, I think there are a lot of users of this router that will support me.
I tried to compile OpenWRT with the patch from this thread - X1200 firmware update but without success, because I didn’t understand for which version it was made.