The Grunfeld might be a good choice if you're into those sharp openings. There can be a lot of theory but there are also ways to cut down on it. The main problem is the sheer number of different lines white can play against it. And some Grunfelds do lead to quick endgames, but that probably depends on Black's choices as well.
I still don't have a good answer to the London myself. If White wants to try to bore you to death there's not a lot you can do about it.
Some books/videos I liked:
https://www.amazon.com/Understanding.../dp/1901983099
^ check out this one first if nothing else, since it covers all the main ideas very well. Then if you like the opening you can refine and update the repertoire as needed.
https://www.amazon.com/Safest-Grunfe.../dp/9548782812
This video has a lower theory approach, I don't like every variation he chooses but I use some of it:
https://vimeo.com/ondemand/foxy26