Fell

Distro:

• First choice: Mint Cinnamon
• If the GPU is very shitty: Elementary OS (Mint Cinnamon expects a basic level of GPU performance)
• If Mint/Elementary are too simple: Fedora KDE

Process:

• For fully switching: Obtain an external hard drive, copy the contents of the Windows partition(s) to it and install your preferred distro so that it takes over the entire computer. This is the most stable way.
• For dual booting: Buy an SSD for Linux, disconnect the Windows drive and install your distro of choice so that it takes up the entire space. Reconnect the Windows drive afterwards and set boot priorities in UEFI.

One More Tip: Don’t frontload them with information, but teach them one thing: How search for and install packages through the GUI (Mint Software Manager/Elementary Store/KDE Discover). Tell them that it’s more like a smartphone apps and downloading software from websites should be a last resort.

The best ones where basically everything works as intended are: OnePlus 6, OnePlus 6T, Xiaomi POCO F1

I have a OnePlus 6T and the only missing pieces are calls and camera. Both work, but not reliably yet. Everything else is pretty much there.