Xiaomi router is very resilient.
As long as the AX3000T keeps its original bootloader (and the u-boot OpenWrt bootloader isn't installed //as long as the devil prompted to try something new - sorry//), there is a 99.9% chance that you will be able to restore the original Xiaomi firmware for the AX3000T via the MiWiFi restore tool or TFTP method.
But yes, UART flash is always a backup plan that also works.