Just yesterday I pinned VLC on my KDE Plasma Task Manager. Why? Because this way I can directly open "Recent Files" from it. I discovered about this functionality just last week with Libre Office Draw. It's so efficient, it absolutely changed how I use my computer daily!

but... why do I bother with this long example? Because IMHO that's from KDE, not Debian. When a distro improve the UX, as I also wish, it can be mostly by selecting the best software in its packages to maintain (e.g. here KDE but yes could indeed be their own custom made package, even though it requires a lot more resource AND other distro could also use them back assuming it's FLOSS) but arguably the UX is mostly of the distribution itself is limited to the installation process.

What you're asking for is distributions to roll their own solutions instead of contributing upstream to make it better for everyone. Distributions and the organizations behind them frequently do things to make the user experience better, it's just that the preferred way to do this is by making the projects they use better...which will just look like a DE version bump by the time it makes it to a distro changelog.