Asus RT-AC68U - Save multiple WAN settings

I am using a Asus RT-AC68U and often need to switch between multiple ISP accounts I use. Reasons range from ISP network congestion/speed to available cap on the account. Regardless, having to change the username and password manually each time I switch is what I would like to eliminate.

Is it possible to save multiple PPPoE WAN "profiles" and just switch between them?
Would updating to AsusWRT-Merlin or DD-WRT allow me to do this?

I am not too concerned about features like...

Asus RT-AC68U - Save multiple WAN settings