After a whole night of playing around with the router I’ve tested every firmware from stock onwards including merlins. Some are better than others and stable with nice features but none of them matched R7000’s performance. So I’ve swapped it for a R7000 again although the user interface and features aren’t as exciting as Asus, the R7000 does what it’s supposed to do very good. Also got an EX7000 range extender and running it in access point mode through a power line adapter for the time being. Range is as good as R7000 if not better and throughput was also as good when I tested it directly wired to router, I’ll be sticking to this router and range extender.