I’ll try a fresh download a little later.
Something that is confusing me though is were has cachyos-desktop-linux-251209.iso come from?
There is no announcement of a 251209, the last official release is 251129. I don’t recall having been able to download a newer version than what was mentioned officially…
Also for the record I can still download the 251129 via the links provided at CachyOS November 2025 Release Changelog