Well, I would start by booting from the GRUB command line. Using the install media can work to fix the system, but this is getting into chroot territory and there is no reason to believe the system isn’t working. Just not booting. Much simpler to use the grub rescue terminal to force a boot, then run all of the grub goodness from there. Basically, if it boots from the disk in rescue it guarantees grub/efi is mounted where it needs to be, from there grub-install on its own should just work. Also, make sure the config you are feeding grub-install is set to output a boot option. When in doubt use the default config, it should work fine.
Get this, those billionaires control the production and distribution of these basic necessities, and attributing a monetary figure to it is the problem. It doesn’t cost money, it costs labor. You get the labor in exchange for fun stuff. This is the crux of the issue. We need a system that can’t be gamed to incentivize hoarding whatever it is we use to denote the worth of labor, as cash does today.
It has nothing to do with cost, it has to do with ridding the problem of the people hoarding the excess wealth for the benefit of an arbitrary group. Where the labor comes do the profits go. If a private individual puts in labor, and that generates a profit from itself, then yeah, they get that. They earned that. The nuance is that they have a community, infrastructure, all of the things supporting their ability to do anything, so any profit comes from the community in some fashion.
We need to get rid of systems of hoarding. 100% tax above whatever 100x the poverty line is, for everyone, that gets dumped into government coffers to subsidize all essential labor. This incentivizes the extra profits to go to the UBI coffers instead of individuals while still giving a huge ceiling to make extra money for labor that generates profit.
I’m just reiterating what Marx was saying. We need to stop focusing on the money aspect and focus on the labor.