I had many problems with installing grub in a dual boot configuration, so much so that I moved to systemd-boot and never had problems after. I don’t know why, but it’s config file approach felt more intuitive.

I’m actually not sure why GRUB is such a popular boot loader that comes packaged with so many distros. Maybe GRUB does something more complex than just bootloading, but I don’t know if most users would care…