Syrup

Right, but still quite affordable compared to similar solution with Proton IMHO

Yeah, best combo for me too

You can try Frost, a web wrapper for Facebook: get in on F-Droid here.

You can also run it isolated using Shelter, another app on F-Droid, get it here.

Same for me, XFCE is light, stable and efficient. I believe that's the reason it's chosen for Debian as default DE

According to their Wiki, other Distros (including DE) are not supported/documented and if you do it's at your own risk. Personally, I wouldn't dare trying that.

Dell provides XPS laptop with Ubuntu on it. It works great and Ubuntu can be replaced with other distro ( I did successfully tested Mint and now Debian 11)

Works OK but makes your connection slow as hell... Not really useful for daily usage.

I don't think so, mostly it's hardening, and few security related software, all FOSS

But you'll need much more RAM, 8 GB is a bare minimum...

The kicksecure documentation is well written. Go here for distro-morphing of Debian 12, step by step things to do are pretty explicit and you can even copy the command lines if you think you'll make a mistake...

You have a link?

This is the best choice IMHO. You have a rock solid OS (Debian) and all possible taken measures to harden it with Kicksecure patch.