Everyone who has problem with original OpenWrt firmware, please read this thread and my solution Xiaomi Wifi Router 3G - 18.06.x / Wifi issues 2.4GHz + 5GHz
I spent a lot of time to adapt HomeAssistant for OpenWrt. Crazy issue with USB 3.0 totally blocks all work. Padavan's firmware allows you to turn-off USB 3.0.