Can the AC1600 v1 make use of the DD-WRT firmware?

I have been through every menu and setting on my Archer AC1600 but cant find where the Operation Mode is, which I need to change it from Router to an Access Point..

I've set up my RE205 as a wifi network extender for my Netgear R7000 router. I have used the same SSID for all wireless networks, eg both 2.4 and 5 GHz bands on both the R7000 and RE205. Devices do co