Honestly shit like that works really well when half of your notebook's keyboard doesn't work anymore. The on screen keyboard is limited and copy pasting letters from texts can be faster. Especially with special characters. Or when you just need an a or s, opening the on screen keyboard again and again vs copy pasting it once and using it as a source - the second one is faster.
I am very sad and desperate I can't afford a new laptop
What's the model? I know a decent bit about laptop repair and I can do some research for you to see whether it would be a massive pain to replace the keyboard.
That's super nice of you. I think it is an HP 250 G7 (that's on the back), I bought it back in like 2017. I'm not very tech savvy and just bought the one a fellow student had and said she liked. It drives me nuts because I don't get how to turn it on or off (I mean I do, but it changes what it wants all the time, you gotta rub it the right way).
Just looked into it a bit and although the part is pretty cheap it's a bit of a tricky repair. If you had 50 dollars lying around and wanted something better than an external keyboard you could just do the whole top case (part that all the internals go into which contains the keyboard and trackpad). Still requires taking apart the computer completely, but if you (or a friend) are feeling adventurous it's not a bad route.
Quick question: how do I figure out if the malfunction is really caused by the physical keyboard and not some soft/hardware issue that has nothing to do with the keys themselves?
Unless there's liquid damage and it's certain rows of keys not working at all it's unlikely that you'd have that sort of partial failure of your keyboard. Even in that case it's still usually the keyboard. If certain keys only work with excess pressure that's pretty much 100% a hardware failure of the keyboard itself.