Triple boot with Grub Menu

Hello I currently have Zorin OS and Windows dual booting on my computer using the grub menu. I wanted to add a third OS which is Mac OS Big Sur which I already know how to setup but I wanted to see how I could get it to also pop up on the grub menu on startup.

I haven't tried this myself 1 to 1, but I have tried having 3 OS's at once with the grub menu being my selector still. What happened in my case is:
install Windows 11 -> Install Zorin 16.3 -> Install a clone of my work PC (Windows 10)

What ended up happening is I lost the grub menu and it kept going into Windows 10. I was unable to reach my W11 install, nor my Zorin 16 one. I had to make a Zorin 16 USB and use the recovery mode on it. That seemed to build a new grub menu where I could use all three and they've all worked fine ever since.

TLDR: I think it will break your grub menu, but it can be repaired with a Zorin USB

Welcome to the Forum!

With another Linux System it would work. But beneath Windows and Linux MacOS? What for a Machine do You have that You can run Windows AND MacOS on it?