Thanks for the pointers.
Problem is, that the current implementation totally relies on every single GPIO toggle to generate interrupt, while the QEP allows me to occasionally read the current state on demand. I can provide "distance", but not distance_count. Nor can I provide total_count. Error_count, if at all useful, I can still get from the eQEP interrupt registers. Last reading ms also doesn't make same sense because we are reading on demand, rather than handling every single interrupt on the GPIO.
Is there no other Ardurover platform where there is hardware similar to eQEP?