Maybe it's because of my limited experience with containers but I can't imagine why on earth you would prefer GUI tools (especially a graphical shell) in a container.
I might be off-base, but when I hear someone talk about running GUI tools in a container, I think about being able to effectively fork application configs/intallations and environments. I run an extremely minimal arch installation on my production machine. It's... nice, I guess. I'd love to experiment with it more and make something even more customized, but I can't risk any downtime.
And a large portion of my computer is command line tools, sure. But I'm also running EXWM, I'm also running Firefox, I'm also running Tiled, and Blender, and so on, and so on. I don't want to get rid of my command-line tools, but I'm not only running command line tools. I want to be able to download a game, put it in a container, mess around with my drivers until it runs well, and then delete the container when I'm done and know 100% all of the customization just went away.
This was what originally got me excited about Docker, until I dug into it and realized Docker kind of didn't work particularly well for that.
My understanding is if I sat down and did the research, I could build something like that with regular Linux tools, but it's time consuming and as interested as I am in the underlying tech, I just know very, very little about how this stuff works.
But I always perk up whenever I hear someone talking about running graphical applications in containers, because in the back of my head I'm mapping that to some kind of fictional computing utopia where I can have complete isolation between processes and treat my computer like a Git repo.
I have been wanting something like you describe for forever. Honestly, the closest thing that I've found to this that works-out-the-box is Crostini in ChromeOS.
I don't love ChromeOS, but if I started building what you're looking for, I'd look at Crostini for inspiration.
Crostini can spawn gui apps through Wayland instead of pure X. That takes effort and I wish they would contribute it back.
Application isolation and the ability to upgrade separate applications and components with their dependencies separately from each other. Less issues with "update X" now broke A, B and C apps... you now have to add a PPA for Apps A and C, but B you'll have to build from source, oh crap, no longer actively maintained... switching to D app which was forked a couple months ago.
Not to mention the ability to easily support different build tool chains combinations, etc. Right now, my preferences are flatpak, snap, ppa, repo in that order.
Not really looking to play with a new linux, Manjaro is next on my list. Currently running Pop!_OS, which has been nice (just jumped this past month, haven't tried a linux desktop in 5+ years before that). I've been relatively happy.
That said, my biggest issues so far:
* need to update kernel and new mesa drivers before putting the 5700 XT video card.
* needed to update kernel for wifi support (intel ax).
* rainbow puke from RGB controllers, the Gigabyte (X570 Aorus Master) support is all but worthless, and the open-source project I saw was actually for windows. For the Lian Li o11 Dynamic Razor edition case, there's open-source Razor drivers, but I'll need to setup a windows drive in order to capture some data in order to support the specific device. I haven't even looked into the Corsair ram yet (which is actually the biggest eye sore at the moment).
I really regret not building another black box. My first two choices of cases without windows were sold out, so I went for the "pretty" case option. Which would be great if I were running windows, but I have no intention to. A lot of money on RGB fans (all matching), water cooling, ram, etc... and none of the controllers have good linux support. Would switch to another controller, but the only one I keep finding is a German company and doesn't seem to actually be sold anywhere. Which wouldn't cover the ram or case.