this is one of the most painful things I've done in a game , and I wanna get one thing out of the way, I'm gonna put a note here and say that I did this while there is way to stop save data from being deleted, (as of current to quit out the game with alt F4) so I'm going to factor that into this guide but i feel that these tips are still gonna be super useful if you plan on going for this achievement, (and possibly the hermit one as well.) with that being said here's three major tips for surviving this achievement. if you plan to go a full legit (or not legit) run of the game.

this is mostly an easy one to understand but in order to beat missions you just have to have a rank above F in the case of iron man mode the E stands for excellent if you worry about It you'll start to crack five missions in so this should be a no brainer. leave the rank stuff for non iron man runs.

this one mostly matters because of the later missions mostly becoming drawn out shootouts (ie every mission at ides of march and beyond) and how little health you have in game,so pick the best armor (and if you can a shield for your squad mates!) and take your time, this ain't a race and you need to be careful, since any mistake can set you back hours of progress, don't rush and make sure to bring your best weapons and stun items.

stress levels are a major thing in commander mode, (think of it like a more painful version of xcom 2)
if an officer has to many issues maintaining ROE let them take a break and don't bring them to the next mission,otherwise they quit and bye bye hermit ;) i"d especially keep an eye out for the mission elephant, since there seems to be a flag that makes any officer on that mission get stressed even if you maintain ROE. (this one is mostly important for the hermit if you're only going for the world, just worry about keeping officer casualties low.)

missions can very in difficulty and sometimes just come down to luck if you win or not (as of current) if anything be prepared to scream if rng is not on your side, and rnjesus does not care for you whether you are good at the game or not he will kill you 8) and in this case of pain, just follow one of the previous tips and take your time. optimize your routing through the missions to minimize the rng of the run and you will tame the wild beast, for now...

like i said one of the more painful things I've done and that's coming from someone that's done a lot of bs things in games. i hope these tips help and I wish you all that attempt this the best of luck!!!
this is also my only guide I've made so i don't expect this to do well, just help people with 2 of the more painful achievements in ready or not!!