NewOldGuard [he/him, comrade/them]

I think that would be absolutely pointless. The advantages of having a system that’s free to study, audit, modify, and contribute to goes away once you make it rely on proprietary software to work at all. In fact that’s not FOSS. There are already desktop operating system that works this way, with an open source kernel and core but reliant on proprietary software, with first party levels of support: they’re called macOS and ChromeOS

Audile should do the trick

I would point you towards EndeavourOS. It’s pretty much just preconfigured Arch, so you get the same rolling release packages as Manjaro and retain access to the AUR. Its a solid project, IMO it does everything that Manjaro claims and fails to

You can also run a distrobox and install stuff normally from whatever distro’s repos, then export the applications so they’re available like native. Works really seamlessly in my experience

I use fedora-based atomic distros for the reliability and security. Nothing else really runs SELinux out of the box and I care about security so that’s a necessary baseline. I roll my own distro though using BlueBuild, and base it off the SecureBlue image of Silverblue. Just using SecureBlue gets you nearly to what I use though

I think it’s like 60-70% and declining nowadays

How’s your experience with cosmic? I’m using a very similar setup with a custom bluebuild image pulling from secureblue. Currently on Gnome but impatiently waiting for cosmic to hit some level of stability