Grub and BootRepair Issues

I have a dual boot laptop. My primary OS is Neon. A while ago I decided to add Ubuntu Studio. Originally, in the Bios I could choose which boot partition to use. If I set it to Neon, I'd see the Neon boot menu, if I chose Studio, I'd see it's boot menu, and if Windows then no boot menu at all. Ever since I installed Neon, if I didn't select Neon quickly at the menu, the computer would freeze and I'd have to reboot again. This didn't seem to be the issue with the Studio menu, so I've left it on that even though I haven't actually booted into Studio in a long time. I decided to get rid of Studio and just go with Neon. However, even after changing the Bios to load the Neon boot partition, it goes to the grub rescue screen. I've used Boot Repair many times over the years and never had any issues with it. But today I can't get it to work.

I have a couple live disks (Neon and Studio) that I've tried, each have the same results.

The first issue is that it complains that I have "legacy" Windows and the boot of my PC is in EFI mode and that I should change it to Bios-compatibility/CSM/Legacy mode. First I tried telling it to go on anyway and it gave me the second issue, which I'll explain in a bit. Then I tried going into the Bios and changing it from UEFI to Legacy, rebooted and tried Boot Repair again. It came back with the same error. When I tell Boot Repair to go on anyway, it then comes back with the second error saying 'dpkg-error detected. ..open terminal (run) "sudo chroot "/mnt/boot-sav/sda8" dpkg --configure -a". So I do that and then get this error "dpkg: error: unable to access the dpkg database directory /var/lib/dpkg: No such file or directory". /var/lib/dpkg does exist.

I can't get any further than this. Any ideas would be greatly appreciated. I really don't want to reinstall Neon to get past this.