First of all, thanks for answering. After reading the reply of the bug report suggesting to try an alternative to Ventoy to make the USB booteable, I decided to try something different first: Grab another iso from the website, and decided to use the full DVD install, that comes with all the DE inside.
Well, I did the same process, no internet, used the graphical installer and all, and to my surprise it installed just fine (albeit slow but that is the hdd that really is a spinning snail). I'd go with Gnome again. After the installation and reboot, the system boot up normal as expected. It was a success. Might try later the suggestion of using something like Rufus and the Gnome live iso to check if it's Ventoy with that specific iso that is causing the problem, or if is that iso that has an issue with my specific hardware and no internet connection. Nothing else to add.
