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These people are giving you retarded advice. What you're asking is easy.

All you need to do is get two flash drives. On one you use the Windows Media Creation tool to create a windows installer and on the other you create a linux installer for the distro of your choice. Linux Mint is a good choice for beginners.

If you end up needing to go back to windows you just boot from the flash drive you made with the media creation tool and follow the screens, protip, delete all partitions and let it make new ones for ya.

If you want to be extra safe, download and upzip this folder on the windows flash drive before you begin, it contains the hard disk drivers you sometimes need if the windows installer doesn't detect the SSD. https://mega.nz/folder/vNoQgQrL#tG7pb3eOcTvBYTHvjUoLAg

OR: You can just install Linux alongside Windows 11 and Grub will usually configure itself to give you a menu on startup with which you can chose Windows or Linux whenever you want. Then, if you decide to return the computer you can use this free tool: https://neosmart.net/EasyBCD/ to remove the linux boot menu and make it look "normal" again. Then just delete the Linux partitions in Windows disk management and resize the main windows partition again if you're feeling nice.

While you can use a bootable Linux USB stick to back up the entire drive before installing Linux proper, there isn't much point because you'd need an even bigger drive on which to store it, and if you're going that far then it would be as well just to attach an entire second drive and install Linux into that instead.

Ideally, get the BIOS to boot that Linux drive first, because the GRUB boot loader usually can also list your Windows drive as a boot option.

You must set it free. If it likes you it will return with a freshly installed Linux.

you have to buy it with linux preinstalled or the bootloader blockchain will not verify the tpm. pretty much need to buy another pc.

This can not be done.