The thing is, the comparison between Trump and Chamberlain is inapt precisely, as you and
A
Admiral Beez point out, Chamberlain was operating from the back foot and trying to catch up to a Germany already well into the swing of not only rearming, but bullying. Not only that, the disparity between the economic presence of Russia v America on the world stage is much, much larger in our favor than even the Brits held over Nazi Germany -- which was itself substantial.
In contrast, Trump is sitting in a position of strength. Even without the war in Ukraine, all branches of the US military sit in a better position both in terms of materiel and quality of troop. The US economy, while not great, is head-and-shoulders above a nominally-smaller Russian economy that is already suffering the strains of war. Trump also doesn't have to fight Treasury to rapidly rearm ... but still he caves.
We can disagree about Chamberlain (and I suspect we do, big deal), but Trump caved from a much stronger position, so far as I see it.
To reiterate, this is only my opinion and I welcome disagreement and differing views. I hope the brain-trust here can and will pick apart the significance of this. I suspect it has more importance than just a photo-op flyover, myself. I think a historical moment happened, and not good.