Get the list of programs you commonly use and figure out if they’re on Linux or have alternatives. Libreoffice, VLC and Okular are good for your case. If you find it limiting and need MS features then browser Office 365 is very good.
The best option would be to buy a used laptop and install Linux, Linux works great on old hardware so you could find something 3-7y old and it’ll run very well.
If you’re coming from Apple try anything with Gnome that’s popular (Ubuntu, Fedora).
If you’re coming from windows try anything that uses KDE (Kubuntu, Fedora w KDE, KDE neon).
If you don’t tinker with things under the hood generally you’ll have a painless polished experience.
Being able to get a modern OS that runs smoothly on a 200$ used laptop is the major selling point for you, rest is extra.