Not related to the refund at all, but: Why would you turn off the monitor and not the computer? Even when idling it eats way more power than a monitor in standby.

Seems like something you would think about while, you know, designign a product? And not after its release?

Just install and try to resolve all your issues (if any) in a dualboot. That way you can always go back to Windows if something doesn’t work. But if your experience is anything like mine, you’ll find that 99% works either out of the box or after some minimal configuration. The only notable exception for me are online games that insist on intrusive anti-cheat software (e.g. BattleEye) and choose not to support Proton/Wine on Linux. Curse you, Escape from Tarkov!

or just install and then shut down?