GRUB/EFI - Divide & Conquer, smart multiple boot solution

Solution 1:

Is there an adequate way to partition a HDD in such a way that every Linux distribution I install has its own GRUB

You can keep the boot folder in root drive itself.Configure distros to have a common efi partition.That should be an ideal setup.

so that one distro shares anything or interferes with another distro at its absolute minimum?

It's unclear what you mean here.Distros cannot share any info with each other on there own.If you mean the os-prober detecting other grub installation and adding the entries then you can simply turn off os-prober for each distro.Other than that you can turn off auto mount if you don't want distros to mount each other partitions.

I don't want GRUB to be overwritten with every new distribution I install for a multi-boot scenario. I would rather want to have a set of pointers in a dedicated partition pointing to multiple GRUB partitions or a similar solution.

In uefi systems grub doesn't overwrite anything.Assuming you keep boot directory in root drive itself and have a common efi partition for all distros , each distro will just create a grub.efi in there own folder in efi partition.

This is the content of my efi (Arch linux)

For the other part -- what you are looking for is a Boot Manager

refind - it will help you manage/boot desired ditro easily

Every time I install new distribution, it changes GRUB configuration and shares the GRUB with other distributions.

One distro cannot share grub configurations with any other distro's grub.It's never possible.Each grub has it's configuration of it's own stored in boot directory.And that's why boot directory is never shared between distros.

how to partition the drive as one distribution uses both the EFI and /boot partitions, while other uses a single /boot/efi partition

EFI partition needs to be mounted in boot directory.Boot directory can be on another partition too.Installers of different distros have option to create a separate boot partition.You can do either way.

There are separated records in the UEFI menu, but they all point to the same GRUB menu.

I can't say for sure but it should point to different grub installations or maybe it can be due to buggy firmware {attach the output of efibootmgr -v}.Attach some screenshots and content of your efi partition.Also the partition structure

I tried answering your questions, if you still wanna ask anything feel free to comment.Also accept the answer if it helped.