@glitch >GNU/thing is so prevalent however is in part because of how insistent the FSFs shitfit was over Linux being named that way
The FSF never asked for the kernel, Linux to be called GNU - all they've ever asked for is for everyone to call GNU, "GNU" and Linux, "Linux", rather than calling GNU, "Linux": https://www.gnu.org/gnu/gnu-linux-faq.html

For OS's that are a combination of the larger GNU OS, systemd and the smaller kernel, Linux, either GNU, GNU/Linux or GNU+Linux are all valid names, as you will arrive at a working OS by installing software only as named, meanwhile if you install just Linux, you'll get a panic() on boot.