“EOL” usually means end of (active) support. Apparently, here it implicitly means “you are required to uninstall this”.
As of Linux 6.17.13, the 6.17 series is now EOL (End Of Life). Please install 6.18 stable and/or 6.12 LTS (Long Term Support). - link
I’m pretty sure, I was attempting to install/update to 6.18 above. And, of course, I had run -Syu/-Syuw multiple times before and updated mirrors too.