I'm wondering if it's possible to dual boot Raspbian, LineageOS, and RetroPie on an SD card? I've looked around and it seems like there is an issue with it not going straight into a bootloader like Grub (am I correct that is what Grub is?). I found one potential answer [here1]1, but the issue is it has a broken link. So I've tried to follow up on the "Grub for ARM" thing (ie here). Meanwhile, the first link 1 also had another answer suggesting BerryBoot. I haven't plugged it in and tried to play with it first (it's a gift so it's wrapped atm :) ), and wondering if this triple boot will be possible to work with BerryBoot, or if setting up the "Grub for ARM" will be necessary? Any other things I may be missing? I've just been jumping around trying to figure out what to do, so any pointers where I might be going wrong would be appreciated.
I've always taken Grub for granted, and don't really understand the differences/advantages of berryboot or u-boot over the other (ie here, I'm not sure which I should prefer, and why).