Numix-Circle has been a favorite of mine as long as it has been around. Now, I mostly use Breeze because it is highly compatible, beautiful, and widely used which makes it less jarring when I use other computers.
Back in the Plasma 4 days I joked that the default oxygen theme was ugly on purpose, so users would be forced to dive into customizing their own configuration (which is where KDE Plasma really shines above the rest). I think the defaults have come a long way, and it's nice to have a stock desktop ready-to-go without much customization.
I highly recommend Framework laptops for Linux. I have not used the Framework 16, but I can attest that Linux support for the Framework 13 (intel 11th & 12th gen) is excellent. I have used Fedora on the Intel 11th gen and Intel 12th gen, everything worked immediately on a fresh install without any workarounds or issues. Other distros might require a few package installs, but Fedora, Ubuntu, and Ubuntu derivatives should work out-of-the-box without any additional configuration. The Arch Wiki article for the Framework covers pretty much everything you might need to know to have an optimized Linux experience with any distro.
Aside from Framework's excellent Linux support, I really have to stress how cool and unique it is as a laptop for developers and tinkerers. This thing is literally designed to be opened up, repaired, and modded. All of the internal components are clearly labeled and easily accessible, there's even a little spot inside the laptop chassis just for spare screws in case a screw ever gets lost! Another awesome obscure feature of this laptop is the ability to use a Storage Expansion Card for dual booting. I just plug in the expansion card to boot into Windows, then unplug it and I'm back in Linux. It is absolute bliss compared to Windows and Linux sharing a bootloader.
I know I'm rambling, but I really could keep going on and on about Frameworks. They truly are unlike any other laptop, in all the right ways.