Of course there’s the suggestion of installing KDE plasma on PopOS! Which will work quite well but to give some info on the others:
KDE neon is mostly for devs and is less well maintained than other distros. Still definitly not a bad choice.
Tumbleweed stronk. Definitly out of what you say my preference though yes, it’s not deb based. You should be able to get what you want though through the app store and the open build service. Really it’s discouraged to find random .debs online and install but OpenSUSE runs on .rpm which are fairly commom.
Kubuntu is also good. Last time I checked it’s a bit slower moving than pop but that’s not inherently bad. Definitly a great “It-just-works” distro. Some people, myself included, dislike snaps which are built in but if you don’t know what they are I doubt you’ll care. Most of the hate is overblown.
I’d caution against endeavor as it’s arch based. It’ll demand more from you, stuff will definitly not just work all the time,and if an issue arises it’ll be the first to catch it. Like the grub rescue error that showed up about a year or so ago.
Don’t use Manjaro. The devs are incompetent and destructive to the ecosystem.
Debian is also chill. There’s always unstable (can’t remember the current name. Debian Trixie?) For something that’s more up to date
Last thing no matter what distro, just like an exe, a .deb is just an archival format like .zip and can be taken apart to be manually installed. I understand not wanting to do this though lol and it’s not always that simple
System76 is also a good option especially if you’re american. They have a broader option set too
On power management though I’m umsure if you’ll get the results you want. It’s hell on windows, hell on Linux, and only within the past few years improved on Mac.
You may find better suspend on a laptop made for Linux though but I don’t want to get your hopes up too greatly.
Other options for good laptops though are starlabs and tuxedo computers. On tuxedo make sure you get the right language and layout for your country
On framework I can personally vouch for them. I have had great experiences with the 13 and there’s a dedicated community happy to help on their forum. Friendly people.
As for slimbook friends of mine who have them have had good experiances too