I'd also prefer support for Wifi 6(e), but if you are on a budget, old standards high end hardware is really cheap on the used marked.
So here is what I recommend: Look at the OpenWRT list of hardware filtered by ax[1], sort by CPU MHz and look through the table for a good Mediatek / MT chipset in the column WLAN Hardware (the CPU sorting is "alphabetical", not natural, so it might be that the most powerful ones are in the middle of the table).
I recommend:
- Ubiquity Unify (AP - if you need a router, don't buy)
- AVM Fritz!Box 7520 / 7530 (not in the list, but a german bargain)
- Linksys E8450 (aka. Belkin RT3200)
- GL.iNet GL-MT6000
- Asus TUF-AX4200 / TUF-AX6000
- BananaPi BPi R3
- Xiaomi AX6000 / AX9000
- Netgear WAX220 (AP)