Your problem may differ from mine, but whenever I’ve been greeted with the command line in grub the solution has actually been in bios. I’ll leave you with my notes, which are a bit snarky after spending a lot of time trying to figure out hot to repair grub, when the solution was 3 clicks in bios:
“Inspiron won’t boot
Goes to the grub command prompt
Don’t fuck with that thing
Restart, F2 to get into bios
Change boot sequence to start the SSD first, not ubuntu
Reboot, itll do it a couple times, but should boot right into normal grub”