Linux

Though there are probably many¹ features im not aware of.

Actually, they aren't many features, and that's one of the main drawbacks. Clear Linux isn't really meant for a general-purpose daily-driver (of course, nothing actually preventing you from doing so, like most Linuxes). It's mainly aimed at DevOps stuff, AI development, cloud computing, container usage etc.

Speed is it's main selling point, but it's speed mainly comes from it's default packages compiled with extensions such as AVX512 and applying other Intel-processor optimisations. Which means third-party applications won't get that much of a benefit. It wins synthetic benchmarks and overall the OS feels snappy, but you can get that snappy feel by using a custom kernel like Xanmod on your existing distro.

And here's the main catch - the package manager sucks, and there's very few packages in the default repos. You need to compile a lot of stuff, like codecs, if you want to use it as a daily driver. It does have Flatpak, but again, if you use Flatpak packages then you'd be missing out on all the optimisations.

It feels weird to me to invest in a distro that focuses on just one CPU manufacturer for a laptop. If I was trying to hyper-optimize a server then it makes sense. But what if you get very used to how this works and then switch to an AMD laptop in a couple years? Or maybe ARM becomes the next big thing?

Clear Linux or ClearOS?

It's heavily Intel-optimized as you can tell from the project's page. The distro is primarily aimed at container workloads but there's no harm in using it as a desktop distro. It's supposedly fast! (according to Phoronix benchmarks).