(of course, M has yet to live with his grief and remorse but he's still better off than OP)

Sorry for the rant lol
I just always liked wondering about this scenario and your take on it is deliciously angsty

I absolutely love how visceral you made Optimus’ expression look. You can see the barely contained rage and disbelief, maybe even envy that Megatron is doing so well on the Lost Light because how dare he come to terms with himself after everything he’s done?

If after surviving Galvatron's Sweep army he felt "a soft rush of sadness" knowing he was still alive, then this would hit like a freight train of frustration/exhaustion

he was happy knowing he could finally rest, that no one needed him anymore. So for him to be brought back to life again without seemingly any purpose after all this would absolutely devastate him

Oughhhh I love this >.>
Optimus fighting with love in his last moments within Unicron proved that despite everything, he never gave up on his principles. That will always make him better than most. Still, he was able to do so much also because he knew he was going to die