I started with Manjaro, and found myself in quite a predicament once I figured out what it means to have Arch under the hood. It was…a rude awakening.
Then I moved on to Debian and Fedora, and from there I gained enough knowledge to manage Arch systems. Now, I have Endeavour on my main computer and OpenSUSE Slowroll on my laptop.
Oh, I should make it very, very clear: Ubuntu is a mess that newbies shouldn’t touch it with a 10 foot pole. Comparing to Ubuntu, even Arch can look appealing for lack of confusion. Nothing that I say goes to support this abomination, and I did not mention it positively.
Generally though, most distros featuring KDE/GNOME will already have everything in one place - but, ironically, not Arch, which actually features three places to look for apps: the official repos for precompiled packages, Flatpaks, or AUR. And without something like pamac - a tool made by Manjaro team available through AUR - you can’t have all three in one interface or through same commands.
If I would choose distro by how easy it is to have everything in one place, this would likely be Fedora/OpenSUSE/Debian with Discover app store from KDE suite. Everything, be it native packages or Flatpaks, is in there, and you can easily select the source for any given app.
As per compatibility, I’m a strong proponent of Flatpaks. They are not significantly harder to manage than any other apps (in most cases, they don’t require any extra configuration), but they will help you avoid dependency issues and they also won’t get full access to your entire system, which is to me a disaster waiting to happen.