Good way of farming Elder/Shaper guardian maps?

I'd like to avoid buying stuff, still lacking currency. So what's a good way of getting those? I have the Atlas passives, I tried running Elder or Shaper scarab+cartography scarab maps, no idea if that works...still no luck. Any other way to increase chances, or is it down to running maps as fast as possible?

Just speedrun as many t14+ maps as you can only for the boss kill.

Here is a quick atlas tree that I put together to speedrun two adjacent t14+ maps for their boss drops.

It has all the adjacent map drop chance and map duplication nodes, which should not only make it easier to sustain those maps almost entirely from the boss drops but also has a chance to duplicate the special map drops you get from the bosses.

In addition to Shaper / Elder Guardian maps, it also drops Synthesis and Conqueror maps.

Also, some currency, scarabs, and uniques to add value to the boss kills.

I added Shaping the Seas to make random map drops more likely to be the two favoured adjacent ones.

Depending on your taste, you could drop some of the clusters (other than the special map drop chances which should be your main source of income I believe) and get other stuff like Intelligence Gathering to passively unlock your safehouses or Sulphite Infusion to bank up sulphite for Delve, or even possibly just getting Packed with Energy for the extra movement speed with Niko missions or Delve scarabs.