Make real backups. Ideally make two or more
- a full disk backup with SuperSuper
- A Time Machine Backup on an external drive
The likelihood of making your machine unusable for a while is non negligible.
Mac
If you want to dual boot with macOS, do some research. Boot loaders and EFI can be tricky.
Holding alt after pressing the power button gives you the option to choose the drive to boot from. Holding cmd + R after pressing the power button allows booting into recovery mode. It allows you to partition and format your internal drive and reinstall macOS.
You can install a newer version of macOS than is officially supported using OpenCore Legacy Patcher.
FOSS principles
Intel Macs often have Broadcom WiFi chips, that need proprietary software to work. As a noob, you should got with a distro that makes it easy to install these or does it automatically for you.
You likely also want to play some video files, so you will need nonfree stuff.
Distro hopping
Install to an external drive or Virtual Machine. You can do that on your existing macOS with VirtualBox for example.
similar to Windows, macOS, customizable
Even the desktop environments, who claim to be macOS like (Endeavour, GNOME), have at best a superficial similarity. Don’t expect a macOS replacement. All desktop environments are different from macOS.
beginner distro
Fedora and SuSE are not beginner friendly. Lots of Linux distros use the same marketing terms of easy to use, powerful, efficient, etc.
Start with Ubuntu or something based on Ubuntu like Mint.
Cinnamon, KDE, and Gnome are all good desktop environments for beginners.



Better for LibreOffice and other software to read and write.
XML isn’t meant to be written by hand.