You may be out of luck for now. https://github.com/sddm/sddm/issues/1399

There is a section here on dual booting using systemd boot. Never used it, but it will hopefully work in your case, or at least point you the right way.https://ostechnix.com/dual-boot-windows-and-pop-os/

Bodhi Linux. Lightweight and beautiful

I have never used those tools, I usually just dd the iso to a usb. I am assuming you are on a linux distribution already. I would download a fresh iso and verify the checksum. Then use dd to write to the usb. I use this format, and of course replace the path to iso bit and /dev/sdx (your usb)with what is relevant to your situation. Just open terminal and type

sudo dd bs=4M if=path/to/your.iso of=/dev/sdx conv=fsync oflag=direct status=progress

You probably already know but you can find the usb’s specific /dev/sdx with sudo fdisk -l

I still use one. I like having a small device for just that purpose. It doesn’t have a touch screen, which is how I prefer it. I despise touchscreens. I like to interact with my phone as little as possible, especially while driving.

You want bleeding edge but are moving to Ubuntu 20.04, which was released in 2019 with a 2025 EOL? No DE from that release’s repo will be bleeding edge. You can manually install the newest releases of software you want, but that’s not really a “just works” solution either. You’ll run into dependency hell at some point. I’m not really sure what you’re going for. But as far as a stable DE goes, and if that is the main concern as implied in the title, XFCE has been pretty darn solid for me.