Linux

Sounds like you need a higher end chromebook. I used Mr. Chromebox to load linux onto my Lenovo.

I've had a lot of thinkpads and currently use an ideapad flex 5. I prefer the smaller form factor for a portable machine I take travelling or out to biz meetings etc. The autorotate and touchscreen work great in Debian with gnome-shell out of the box. No pinch-to-zoom but I believe that works on KDE plasma out of the box.

I personally love my Framework 13. Not sure if the battery life is up to your standard, but the new models are plenty enough for me.

I would get a Thinkpad, either used or new, with that budget. Generally all the hardware will work out of the box, with the possible exception of the fingerprint reader if it exists. RAM and SSD should be replaceable, so if you purchase new just do the upgrade yourself to save some bucks.

Get a Librebooted Thinkpad T440p or similar and then upgrade it (SSD, 16gb ram, etc).

Get an Apple, thinkpad or dell.

The main thing that determines if a computer can be repaired is parts availability. Those three have great parts availability almost universally.

If you wanna run macOS you need a Mac. The t480 is a good recommendation for thinkpads, but don’t worry about ssds or ram yet, just get the one with the processor and display you want (it’s the midrange 8th gen ones). I don’t know the dell world enough to make a recommendation but someone will do so.

Use the gentoo and arch wikis to check what problems people have out of the box with whatever model you’re looking at.

People will say you need amd. This is either paranoid or based on recent events. Neither apply to you.

People will say to get a framework or some equivalent. They’re expensive and a moral/ethical statement. This doesn’t apply to you.

I can reccomend huawei laptops with metal chassis. I've had my matebook x pro for around 6 years. My past laptops made of plastic disentegrted over time

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.

Ummm, good luck. When I tried to use Linux on a new machine I built and had a bunch of problems, people on the forums told me to wait six months for someone to write drivers for the components.