I don't live in America, I live in the UK. You are speaking about PC's which are already built, they will cost 2k+ regardless for a low end PC. Custom built PC's are always cost effective and generally work out cheaper.
The national minimum wage in Australia is $753.80 per week, for a 38 hour week, or $19.84 per hour. So there is literally no excuse, just sheer laziness.
If you want to play with a keyboard you would save and purchase a PC, regardless of the dilemma you're having, even if you used K&M and entered PC lobbies you would still get "tortured" (as you put it) on console due to the FPS cap from the console and high MS count which you most likely have from your monitor/tv.
"there's so many advantages with mouse and keyboard and it's not fair."
This statement right here is why M&K Peripheral support isn't allowed on console or players would exploit it and "torture" controller players with their flicks and all sorts of other mechanics which are unavailable to controller users. Regardless of peripheral support, if you are not good with a specific peripheral you would not have invested into it in the first place.
Rome wasn't built in a day, and neither we're gaming skills. If you wish to practise here is an easter egg you can use in the training grounds to improve your aim.
I'm sorry but if I could afford a custom built PC while at university 8 years ago and on a tight budget I'm sure you can too. I am done repeating myself on this topic, enjoy the rest of your day.