Ah that's interesting. I've been generally ok, but what I did do was I installed regular old Ubuntu (BTRFS by the way, ZFS also too much hassle), then I installed the KDE full (meta package) on top, and just reconfigured to start with SDDM display manager and launch into KDE. So effectively Kubuntu but starting from an Ubuntu base. And then sometimes I'll randomly decide to switch back to Gnome for a bit and sometimes I prefer KDE. But the great thing is that I have everything available and any possible dependencies. Weirdly that's been super solid, although during one upgrade it made me uninstall KDE but not during the next upgrade. But yeah, I like it, and then whenever I try out other distros I just seem to be cursed entirely (Fedora for some reason is utterly cursed for me, just bizarre problems straight out of the gate on VMs or bare metal), or I end up spending months messing about with something and then saying what's the point in this even existing.
On the ZFS point, if you read what people say on the internet, ZFS is soooo much better than BTRFS and it's clearly the only sensible choice. But in reality it's just so much hassle, so many bugs, and you've got to worry about your RAM and your exact settings for it and all this nonsense. And these are the people with the gall to say that BTRFS is unreliable, despite the fact that you can have a 12 bay Synology NAS with BTRFS and pull the power cord out all day long with no corruption whatsoever, and then with ZFS it's make sure you do this and make sure you change that.
So at this point I'm very jaded on what anyone in the usual forums says about Linux, and I'm down to saying Ubuntu because as much as I like to tinker, I have so much else to be doing with my time, and it's so annoying with especially Arch based things to have them break things and then expect you to read release notes before you press the update button. I also went down the non-systemd distro rabbit hole, and again what a waste of time. Hours trying to do basic things and stuff just not working.
Also be really wary of using LLMs to help you with tinkering. I find they just leave out vital details, and if you go back and question them they say 'oh yeah, you're absolutely right, i did leave out xyz really important info, let me do that again for you', meanwhile you've already bricked your system.
By the way on the packaging front have you tried messing around in Distrobox? It's a really nice really easy way to install any app from any distro on any distro. Super quick and easy, export apps to your desktop so you can run them as if it's native, but they're running in little VM style containers of the target distro, but still with access to your user's home folder etc. So if you need a version of an app which is only available on another distro, you can use Distrobox to install just that app and have multiple versions and manage them all side by side. Totally negates the need for distro hopping. Of course this assumes that the stable base is working well enough for you, which to be fair it sounds like for you it isn't.
But for me all I'm worried about with the distro is a stable base, good drivers and default settings to save me time, and the kernel version, and timely security updates. Then everything else can be Distrobox or whatever other package formats.
