Debian Stable as base OS, then activate unstable repos in a sandbox/container. Maybe even Distrobox for newer Apps.

How about miniPaint? Its mostly in JS.
https://github.com/viliusle/miniPaint

Maybe Piwigo: https://github.com/Piwigo/Piwigo

Not Fedora, but MX Linux and Antix are good for persistent installation on usb-sticks. See here: https://antixlinux.com/the-most-extensive-live-usb-on-the-planet/

His stance on desktop security may be very hard. But his views are not far off from that of other known security researchers like Micay (Copperhead/GrapheneOS), Rutkowska (QubesOS), Matthew Garrett (Red Hat, Canonical), Solar Designer (Openwall) and others. They heavily criticize Linux and *BSDs to make us aware of all its shortcomings.

Systemd is hated by hobbyists mainly because it invalidates a lot of their hacked together wisdom ...

Maybe these people dont hate systemd but want choices for a more minimal/barebones OS. Not to gatekeep Linux but to install a more energy-efficient, lightweight Linux OS for themselves like many Alpine, Debian and Arch users do. They believe in the KISS principle. The concept that less complexity equals better security ("less is more").

not sure about the other ones, but "madaidan" (Kicksecure/Linux Hardening Guide) and Daniel Micay (Copperhead/GrapheneOS) are well known security researchers. See Daniel Micays take on Systemd:
https://old.reddit.com/r/GrapheneOS/comments/bddq5u/os_security_ios_vs_grapheneos_vs_stock_android/ekzo6c0/
https://forums.whonix.org/t/fixing-the-desktop-linux-security-model/9172/2

Suckless.org's take on systemd is pretty well researched. All sources inside.

Some other critics are Ted Tso, Torvalds, Volkerding (Slackware), ... See https://en.wikipedia.org/wiki/Systemd#Reception
https://www.zdnet.com/article/linus-torvalds-and-others-on-linuxs-systemd/

There are some security, privacy and stability advantages of other init systems over systemd. But for most people systemd should be fine.

See here for further info:
https://madaidans-insecurities.github.io/guides/linux-hardening.html#choosing-the-right-distro
https://forums.whonix.org/t/fixing-the-desktop-linux-security-model/9172/2
https://www.unixsheikh.com/articles/systemd-isnt-safe-to-run-anywhere.html
https://unixsheikh.com/articles/the-real-motivation-behind-systemd.html
https://suckless.org/sucks/systemd/
https://without-systemd.org/wiki/index_php/Arguments_against_systemd/
https://nosystemd.org/

Also getting encrypted dns to work with systemd is pretty tough and unreliable in my experience (with debian and opensuse). See here https://github.com/DNSCrypt/dnscrypt-proxy/wiki/Installation-linux

Looks like there are some security, privacy and stability advantages. But for most people systemd should be fine.

See here for further info:
https://madaidans-insecurities.github.io/guides/linux-hardening.html#choosing-the-right-distro
https://forums.whonix.org/t/fixing-the-desktop-linux-security-model/9172/2
https://www.unixsheikh.com/articles/systemd-isnt-safe-to-run-anywhere.html
https://unixsheikh.com/articles/the-real-motivation-behind-systemd.html
https://suckless.org/sucks/systemd/
https://without-systemd.org/wiki/index_php/Arguments_against_systemd/
https://nosystemd.org/

Edit: also getting dnscrypt to work with systemd is pretty tough and unreliable in my experience (debian and opensuse). See here https://github.com/DNSCrypt/dnscrypt-proxy/wiki/Installation-linux
This could be a problem if you are planning to use encrypted dns.

The closest thing to clean install is Ameliorated AME or Atlas OS. Check that out if you really need windows.

This. Trusty old lawnchair2. I can group all my apps in folders and have a separate menu for island/shelter apps.

Debian Stable is a solid choice as it has the best support and is a hassle-free experience. Maybe with KDE Desktop. Its the most userfriendly windows-like desktop i know of.
Optional: You can also install the MX-Tools from MX Linux to get some comfortable GUI system tools.

Just use a second phone for that proprietary stuff. So you dont have to comprise privacy/security on your main/private phone. Also a huge fan of xprivacylua to isolate proprietary apps and feed them random data.

How about Profiles and Community Achievements? Something like Retroachievements?