The new Redmi AX6000 (take apart here) seems a quite good hardware for its price point (CPU MT7986A 4 cores@2GHz, 512MiB RAM, 128 MiB Flash, MT7976GN for 2.4GHz and MT7976AN for 5.0GHz) and it supports 802.11ax (4x4:4) on both bands.
However it is not yet supported by OpenWrt yet. There is already a topic about adding OpenWrt support to this device: