So... Mainly title.
I think something like adblock-lean (super tiny) or adblock-fast (supports DOH) can be used on devices with limited resources like E750v2 which won't handle ADGH.
While this solutions not so advanced and don't have so much features like ADGH, thay still can block ADs. Which is better than nothing.
P.S: You should also recommend to use SD card for filters storage not to wear-off router's flash.