So I've had enough from partitioning my HDD between Linux and Windows, and I want to go full Linux, my laptop is low end and I tend to keep some development services alive when I work on stuff (like MariaDB's) so I decided to split my HDD into three partitions, a distro (Arch) for my dev stuff, a distro (Pop OS) for gaming, and a huge shared home partition, what are the disadvantages of using a shared home (yes with a shared profile, I still want to access my Steam library from Arch if I want that)
Another thing that concerns me is GRUB, usually when I'm dualbooting with Windows, the Linux distro takes care of the grub stuff, should only a single distro take care of GRUB? or I need to install "the grub package" on both? Do both distros need separate boot partitions? Or a single one for a single distro (like a main distro) will suffice?
Another off topic question, my HDD is partitioned to oblivion, can I safely delete ALL partitions? Including the EFI one? I'm not on a MacBook, a typical 2014 Toshiba that's my laptop
I was dualbooting 2 Linuxes for a long time. All that you need is to install GRUB once on one of the distros, but having two or more bootloaders in the same EFI System partition is generally harmless, and might happen due to how some distros' installers are written. In that case the BIOS boot order will decide which one to use. Either way, you only need one boot partition.
It is safe to delete all partitions on your hard drive if and only if you have backed up any important data on them. It's basically the same as installing a new hard drive. The installer for your distro will be able to re-create all of them.
I have personally never used a shared /home between multiple distros, but based on my experience switching desktop environments, there are likely to be conflicts between files that lead to bugs. Arch and Pop!_OS will have vastly different versions of most software, and it's possible that changes to a config file in one distro may break the program in the other. Shared /home is better for if you have just one OS installed, and reinstall it occasionally.