I don’t claim to be any sort of Amara expert, but I have put a fair few hours with her now, and do run a level 50 in M4 at the moment. Haven’t had a chance to try Takedown as yet however. “Life gets in the way” and all that, but hopefully soon.
Until very recently, I was using a build much the same as yours, but with some minor variations: build
The only major differences being the extra points in the Brawl tree (extra damage from Personal Space is very helpful, and multiplicative), and the build relies on health regen/sustain from both an Otto artifact, and a Phasezerker CMOD bonus to Clarity (as opposed the going further down the Fist of the Elements tree for Sustainment).
For this sort of build, I was mostly using high rate of fire mid-range elemental weapons, like Rowan’s Call, Lucian’s Call, and various elemental SMGs. Perhaps against the norm, but I also run Radiation/Cryo/Incendiary as my main three weapons, as the former two still deal with flesh well enough on higher difficulties (unlike Shock or Corrosive), and get an intentionally small amount of added Action Skill element damage via Infusion without penalty (mostly assigned to Elektra for easier shield burning, regardless of weapon).
For the rest of the gear, I use an annointed Transformer (damage reflect on action skill end), and grenades are switched around regularly, mostly for utility or useful annointments. At the moment, my fourth weapon is a Brainstormer, which can also help with CC and shield shredding .
For the most part, this build seems to perform pretty well for me in M4. It’s not a one shot boss destroyer, and depending on your playstyle, could perhaps do with some more defensive skills from the Brawl tree, but gets the job done well enough If you’re smart with using cover and your Action Skill (TTB+Stillness of Mind) for Crowd Control as needed.
A lot more recently, I picked up one of the new Spiritual Driver CMODs, and have been playing around with builds using only Fist of the Elements and Brawl trees. Definitely a lot more tanky for the tougher content, and you don’t lose any damage either. Catch is, you need to farm the CMOD in M4 as a unique drop from Sylestro, and depending on RNG, it could take a while… I was lucky enough to bag a decent one after about 25 attempts or so, but others have taken a lot longer (and shorter) timeframes too. RNG is RNG…
In short, there’s no reason you can’t tackle M4 with your build I think. Elemental weapons are key though, and high ROF helps out in a number of ways.
Hope this helps!