This is the first I've heard of ublue, very interesting project. I started using Kinoite around the time SteamOS 3.0 details were coming out. My Arch install had just shit the bed and I thought it'd be good to get familiar with how the immutable OS might work. I was skeptical at first, but still going strong on the same install probably around 2 years later. I was skeptical at first, but once I got in it and started daily driving, I realized this is the future of Linux.