Linux

Now that you've convinced me this might be the best course (I only see less problems than other distros would have)

Sometimes, software, especially install scripts for something, are less common for Silverblue, but executing those is very risky anyway and I never felt the need for it.

And, as I said, some things just work differently. But NixOS is one million times worse than that in that regard, so don't worry about it. You shouldn't have many issues.

any recommended reading or key concepts I should look into? Any particular flavor(s) you'd point me to first?

I don't know. In my opinion, my post should cover most stuff concepts and differences.

Don't worry about it, you'll use Flatpak anyway most of the time, and it updates itself automatically, so the package manager (rpm-ostree) doesn't matter much for you.
You can still use your prefered package manager (apt, dnf, etc.) in Distrobox.

Other than that, just don't worry and use your laptop for whatever you want to do.

And about flavor choice, there are a few options:

• Bazzite is mainly if you game a lot
• Bluefin and Aurora are the same, just in Gnome or KDE. It's basically Bazzite without gaming stuff
• Secureblue, which features security hardening tweaks
• Wayblue, which is with River, Wayland, and more
• And of course all different DE-spins, e.g. Sway, Budgie, etc.

Just go to the uBlue homepage and see for yourself what appeals to you :)