I was initially very disappointed that the XM5's can no longer fold down like the XM4's, but if you look at them side by side (YouTube time stamp 6:19), the footprint of the folded down 4's aren't considerably smaller than the 5's. Though the new case does seem to be a bit bigger than previous generation. The new ones are also likely more durable since the hinge of the XM4's seemed to be a frequent point of failure.
I agree that comfort/weight is the most important factor for headphones, especially for extended listening periods, which is why I never even considered the APM's.
Huge fan of the new Sony redesign though, they look so much sleeker and minimal compared to the XM4's. Just ordered a pair of the XM5's for my upcoming vacation to Asia. I'm sure they'll fare well during my ~16 hour flight.
Also, in the video you mention that the AirPods Max are often on sale, but didn't mention that the XM4's can also be regularly found for less than $300. Great deal if the new features and redesign doesn't matter much to you.