I tried to look for any kind of entry level AX router, mainly to have some upgrade, but also to have some (a lot of) fun with openWrt.
Just looked up some brands and so far what I saw, all models were based on Broadcom chips = not good.
Simply put, I'm not sure what to think, I find openWrt a fantastic solution, tho I'm just jumped on the boat recently, started to tinker right with two not yet supported devices and managed to run both with openWrt pretty much flawlessly and I have to say I'd gladly experiment further with stuff from the AX palette as well.
About the Broadcom situation however, I don't know how it will look like in the near future. Anyone know something closer - simply what to expect? Even about supporting older models? Is there a way chosen heading to regarding Broadcom?
There are plenty ipq807x based options as well (support under development, but still having quite some road ahead); ipq60xx seems to be entering the broad market as well (but support for that will take even longer).
It won't improve nor should you expect it to. They don't care. You shouldn't care for them either if you want something that supports OpenWrt.
With a bit of looking around you can find some Mediatek based 802.11ax stuff and that seems to be performing rather well. I haven't seen them in higher end stuff though.
You could wait around for Qualcomm AX stuff to become usable/viable, but that's a long shot, and ath11k (their 802.11ax driver) doesn't look to be in much better shape than ath10k (their 802.11ac driver).
Cudy is OpenWRT friendly, providing an OpenWRT build that can be GUI flashed. Cudy's OpenWRT build can then be used to GUI install Native OpenWRT Releases and packages.