It really irks me when ppl characterize the Pale King as a coward or as giving up without trying.
Cowardice, to me, implies that you can and should do something, but didn't due to wanting to save your own hide or avoid some inconvenience to yourself.
But there was actually nothing he could do anymore, all his plans had failed.
He was defeated. Out of options. Impotent. There was nothing he could do & it didn't make a difference if he was there or not. He was up against a sheer force of nature... and was all but stomped in the ground in that contest.
(If you wanna be cheeky you might even say that "the end was inexorable, the outcome set, whether [he] remained or not")
Far from "giving up without trying", he is, if anything, consistently characterized as refusing to accept the inevitable / not giving up when some would say he should have. (particularly since we have the contrast of Vespa calling it folly to keep fighting & just deciding to wall herself off)
The Plan was already a desperate Hail Mary / last resort to "break the laws of nature" after all other options had been exhausted, & something he likely never would have considered without a figurative gun to his head. He had to swallow his morals, compromise ideals, ruin his marriage and sacrifice his most loyal, most competent underlings...
And it still didn't work. He just made everything worse. (and laid terrible burdens on the 2 kids he had in the process - well, the 2 that he knew of.) - and he knew it, too.
An egomaniac who thinks he's always right & can do whatever he wants wouldn't feel guilty or ashamed; They certainly wouldn't give all the credit to the 4 sacrifices while he thought the plan worked (judging by the monuments) only to place all the blame on himself when it failed.
Did ppl just not get the implication that what seems to have haunted him the most in the end (besides the obvious stuff with his family) was the memory/thought/impression of his faithful, loyal underlings patiently waiting for him to come with a solution that he just didn't have? ("We will wait...") - the actual retainers are of course dead all over the ancient basin, he never did make it back to them.
But that's not cause he didn't give a fuck. If anything the thought of them was probably the main refrain playing in his mind in his last days. He just couldn't save them no matter how much he wanted to. No matter how much he was willing to give everything. Nothing lasts forever & allat, its like, a whole theme?
He was probably always the one with the plans & the visions & all the answers, but this time, there wasn't an answer, & he couldn't deal with that. Probably cracked his whole self-concept - who needs a King who can't protect his people? Who needs an engineer who can't fix the problem? Or a God of Enlightenment who doesn't have answers?
And that's without getting into the whole implication that he most likely offed himself to create the charm you find on him, to buy one last faint theoretical chance of a future.
If he was a coward he would have taken the handful of people he cared about the most & ran off to greener pastures somewhere.
Or just forcibly exiled all the moths from his Kingdom. "Sorry guys, you may have been loyal to be since the founding and i know i promised you stuff, but this scary lady who is more powerful than me says you belong to her & I don't want her wrecking the rest of my shit to punish yall."
I totally started out in the camp of "It's neat how they keep him all mysterious & open to multiple interpretations & shades of grey" but ppl get just so gleefully sadistic about the bashing & dismissive about twisting everything into the most villainous possible reading (the most boring cliched flat villain possible, too.) that I'm just tempted to join the apologist squad out of sheer compassion from seeing ppl endlessly beat down on someone who ultimately lost everything, clearly had a lot of regret, had zero illusions that his deeds were anything other than ugly & desperate & basically broke when he realized the full implications.