Well, overall an understandable course of action, albeit a bit unfortunate (for some).
At least for me, the question here is: will this possibly create more work than problems over time because you still have to maintain the old versions?
But there is no question if some things (like Yaru for now) don’t work at all - I’m curious how theming will work at all in the future (with libadwaita) or whether theming will have to be reduced to the bare minimum anyway. Like colors and icons. In that case you could go all in with GNOME 42 and use Libwaita… if of course the quality of the apps and programs in GTK4 is good enough. From what I’ve seen, the apps are primarily adjusted, the first point release should take about 3 weeks and is maybe in time for Ubuntu (when reading the PS part).
But I think you have a lot more insight than most of us, it’s clear that each of us would rather have the freshest and newest. Because it’s an LTS release it looks like you have to think a little more conservatively and can’t fix with updates over the next few weeks after the release – because the release ISO has to work flawless.
PS: The time from the GNOME release to the Ubuntu release is also very short, would have recommended just to make some more time here. One week more time for the developers, still a 22.04 release. Don’t think this will throw anyone off course. Most of those who need a stable system wait at least a few weeks with the update anyway, even after an LTS release. Recommended for every release in the future if you build on top of GNOME. IMHO of course 
Thanks for the great work!