The guy is the lead dev of the Budgie desktop environment. Budgie started out kind of reusing components from GNOME, but Strobl has been rather frustrated with GTK and the directions it took with GTK4, for various reasons: https://joshuastrobl.com/2021/09/14/building-an-alternative-ecosystem
(The disclaimer is important, some opinions on what alternative to use changed, but the frustrations with GTK remain.)
My workplace preinstalls Ubuntu, personally I’m using openSUSE. I don’t even think that Ubuntu is particularly bad, I’m mainly frustrated with it, because it’s just slightly worse than openSUSE (and other distros) in pretty much every way.
It’s less stable, less up-to-date, less resilient to breakages. And it’s got more quirky behaviour and more things that are broken out-of-the-box. And it doesn’t even have a unique selling point. It’s just extremely mid, and bad at it.