The beauty of Linux is that it'll run on almost anything. I recommend second-hand office desktops for your use-case, you might find a good deal and get peripherals with it. If you somehow manage to come across GPUs at your price bracket, avoid Nvidia; poor drivers, support, corporate hostility etc.

My first distro recommendation is going to be a bit different from the usual, purely based on my experiences with other popular go-to distros. I'd recommend you try Fedora KDE, Fedora is a wonderful distro that always makes you feel welcome. KDE is a lot less resource demanding than Gnome, and is the desktop that ships with the steam deck. Personally I don't like Gnome since it's a bit Fischer-Price my first DE for me, but I encourage you to try everything.

I'm using the Budgie DE by the way, it's a good middleground between Gnome and KDE. Fedora provides "Spins" for all major desktops.

If you're feeling brave I'd like to quickly mention a version of Fedora called Fedora Kionite, it's whats poorly named an "immutable" distro (Atomic is a better name but don't worry over that right now). Very basically these distros restrict access to the core, or base, system files; which massively improves security and reliability. I use Fedora Onyx which is immutable with the Budgie DE, Kionite is KDE. Immutability is very new in the pseudo-mainstream and very much in it's infancy, so it will annoy you at times if you choose this path. But it has massive benefits and, I think, is the future of the Linux desktop.

I'm assuming this is your absolute first adventure into the FOSS world, which I know is probably wrong since you're on Lemmy, but I'm also still going to mention you should use the Firefox web browser as you said you were doing JavaScript. Firefox is the absolute most popular browser on Linux and has amazing developer features.

We're all eager to help budding penguins on their journey, so feel free to message me directly anytime for support or make posts right here.