It depends on the project/container. Some containers run Debian, some Alpine, some Ubuntu. I mostly rely on the community scripts from here and use the defaults.

https://community-scripts.github.io/ProxmoxVE/

I guess everything that supports containers, QEMU and KVM is compatible to use as a guest OS in Proxmox.

I would recommend to check out Paralives instead

Yes, as I said it’s a debian base. But Proxmox is built for servers and using it to host and share containers or virtual machines is super simple. Especially with the community helper scripts that can set up different self-hosting projects within minutes with minimal tinkering.

Personally I would recommend Proxmox. It’s a debian based distro for hosting containers and virtual machines

I think Linux Mint would be a good first distro.

I recently learned about a project called Operese. It is a Windows to Linux migration tool that also sets up Kubuntu. Kubuntu is Ubuntu with the KDE desktop environment instead of the GNOME desktop environment. I don’t know how well that tool works since I never tried it but it looks promising.

There is also a new project called Winboat that is meant to make it easier to install and use Windows software such as Adobe Photoshop