I will be using this computer mainly to write documents, make the occasional presentations, browse the web, and watch videos and movies. So no photo- or video editing nor gaming at all.
Then go for a Raspberry pi 3. (No, not rpi 4 or the rpi 5 one). It’s cheap, with a power draw low enough to leave it running 24/7 (it will not increase your energy bills by the slightest). Downside is that you’ll have to learn some Linux “tricks” that will (definitely) “grind your gears”, but eh… it’ll be a fun ride if you are willing to lose some sanity for the sake of enjoying a “It’s like nothing is happening to my power bills at all!” power of the convenience it’ll bring to your life and your lifestyle as well.