I coudn’t possibly recommend a distro that I know for sure supports the resolution you’re using (I don’t have a display capable of that, anyway 
) and my own experience has been limited to Centos (headless) and Ubuntu for my dev environment.
I can say that I know Ubuntu offers a kind of ‘try-before-you-install’ installer so you can just run it from a USB drive/key.
In addition (regarding Ubuntu), to some of your other requirements:
- It’s clean (subjective)
- You can opt out of the bloat by customising the installation
I haven’t ever tested it for performance, although from personal experience I cannot say that I’ve ever noticed any particular issues, but that will depend greatly on use case.
As for isolation, again I’ve not used it, but there are a few articles that discuss and introduce it: https://docs.ubuntu.com/core/en/guides/intro/security
I’m not trying to sell Ubuntu (edit: I know you expressed a dissatisfaction for it); it’s the OS I’ve used predominantly for the last couple of years when I wanted a gentle intro to working on a Linux system and seem to have stuck with it since 