Upload & Sell: Off
Things get carried away in the expenditure department on this forum.
I used to have a 24/2.8 af I think it was pre D. Good lens. Ken Rockwell claims all 24/2.8's are the same, basically. 1970's and up I think. Who knows but an old used one might be an option.
Check compatibility though. Not terribly familiar with Nikon digital but you may need a G lens with your body for af.
What fl do you use now? On your 18-70? If you aren't using 24 that much now, probably no point in picking up a prime. You could always go "old school " and pick up 24/2.8, 35/2, 50/1.8, 85/1.8 and have f/2 throughout the longer end of the range. Of course I prefer to be able to change fl with minimal effort, but some prefer primes. And in general they are considered to have have better iq.
I prefer zooms even if I get a slight quality loss. You seem to want absolute quality. That might be an argument for primes, though their advantage seems overstated.
I think you should try primes. Perhaps better quality. I have heard good things about 85/1.8. Maybe even less expensive if you can buy used compatible with your camera.