#(roughly)

on a single course of action.

and that resulted often in delaying the actual result of any decision-making process they had, often tearing down Sentinel's proposals and rebuilding them to accomodate everyone

Which, with Optimus as the ultimate decision maker, does not happen; because his is the body and they cannot physically interact with the real world in any way that matters, meaning that keeping the decision on track and effective is more important than ever... especially with a guy who does not really give a shit about authority, and while he do holds respect for them, has no real problems telling them "can we hurry the fuck up? is this proposal good or not?"

and Sentinel does not see any of this. He sees just Optimus taking the data he presented, and approving it 1 or 2 cycles later with a "you did a good job!"

given this context... i think it's safe to say the 13 were NOT, in any way or form, in agreement with Optimus when he chose to reinstate Sentinel as a tactician. And were even less happy when Sentinel casually dragged them to backhandedly compliment Optimus over his leadership (you do not see it in the comic i made but Optimus essentienlly divebombed on the methaforical emergency mute button he has for them to actually listen to what Sentinel had to say)

in their eyes nothing had really changed to how they acted and the final result of each debate was on the same line as when they were alive, so to them, it really was just Sentinel spitting slag at them for no reason other than personal favoritism - it took some time to take in what Sentinel actually said afterward

After that and some more time - while none of them will truly like him ever again - i think at least some of them might set aside their pride and actually reflect on everything that happened and what Sentinel said about his own experiences with them; which in their credit, is not an easy thing to do when you're basically your Planet/God's specialest little boy from the get go

I think ultimately at least some of them would accept that Sentinel, for as much of a selfish asshole as he is and for as horrible as it was his course of action, was ot unjustified in his dissatisfaction with them or how they were leading the war.

I don't think they would all admit fault over this, but i can see Zeta and Prima being the first to actually mention to Optimus that they regret how things went, and that if they acted differently, perhaps things wouldn't have reached such a desperate state.

(sorry for the giant lore dump, i'm very passionate about robots and i spend an unreasonable amount of time thinking about these things!!)

as for th second question.... honestly? Both options are good.

He could be the last remaining around of an hyper specialized group of tacticians - possibly their leader given he was the primes' first aid - who were constructed specifically to serve during the quintesson war, and with the others having either died in battle long prior to the fall of the primes, or (arguably worst option) from over extersion - like a computer dies faster the more you push it to its limits

Or he could be a single case! One single guy specifically built around what was required from the primes, with a processor powerful enough to run simulations of every possible scenario given enough data, a frame designed to support the heat and strain, and skilled enough to shoulder the whole war's planning from top to bottom all on his own if necessary... but not much else. Just an hyperspecific tool.

honestly i'm tempted to go for the second option, mostly because the idea of Sentinel having functionally no real other option besides logistic and planning related jobs BY DESIGN is kinda painful, an honestly something i can see.

i have no idea if functionism is a think in TFone, an i genuinely hope not, but i cannot see Sentinel having an easy time when his frame is so... odd. Off even. Like he is a starship, sure, but how he is supposed to fold to turn into one? you cannot tell where is what, hell you don't even see a cockpit on his body. how are those wings meant to fold to turn into things a starship can fly with? can he transform comfortably? can he at all?? was he made with in mind a possible life after the war, or was his whole existence planned around his function in the war, period?

i'm not going to go on a rant here but you are right, his odd frame definitely put him in a weird position, especially in regard of ethics of cold constructed transformers

sometimes on my own i joke that Solus made a convention where she laid down at least 25 laws/articles for the ethics of cold constructed mechs and what is and isn't legal to construct a mech with or as, with Sentinel alone being the inspiration for at least 5 of those articles lol

(because like, cold constructed HAVE to exist given that for 50 metacycles the well of AllSpark has been dry and we have mechs younger than that. Meaning there HAS to be some kind of regulations to how mechs are constructed.)