Which of these low priced routers work best with OpenWrt?

128 MB RAM are insufficient for a device with two ath10k radios.

Only hardware revision v3 is usable here, v1 and v2 are unsupported Broadcom variants. If you can guarantee to get a v3 device, it should be a great option.

Add AVM Fritz!Box 4040 and ZyXEL NBG6617 to your list (~70 EUR), both are ipq4018 devices with 256 MB RAM.