Kingdom Rush Vengeance how to beat The lost empire Iron Challenge on impossible

Specific level info:
This level is pretty easy. Literally just spam mummies. You have so much gold, so just keep spamming them on cooldown. Note that they take a while to come out so you can't just buy them when needed. Seriously, just keep spamming them.
General DLC and video info:
The new DLC for Kingdom Rush Vengeance - Hammerhold is finally here! I have recorded some tutorials for the new levels, as some of them are pretty hard.
I use only free towers and heroes and try to make my strategy as consistent as possible while requiring minimal skill from the player.
I play on the impossible difficulty and without the Pit Lord upgrade, to minimize RNG. If I used the upgrade I wouldn't know if I succeded because of it, or because of my strategy. So, as you will presumably be playing with it, the levels will only be easier for you.
I also intentionally do not micro Asra or my units efficiently, letting them die even when unnecessary. This is, again, because I'm trying to make my strategy as simple as possible, and as consistent as possible. The levels all get much easier if you get her to instakill a specific enemy or stall enemies with barrack micro. I try to make barrack micro easy, mostly just "place them in a specific spot and don't touch them".