How do I fix extremely poor starts?

Not a sprinter myself, but there's a few things:

1.5x BW squat both means something and doesn't. I always hear 1.5–2xBW squat is what most male sprinters are capable of, with some being stronger and some being weaker. However, not all squats are equal. 2xBW half squat is not impressive. 1.5XBW squat all the way down is much more impressive. Furthermore, while force production is certainly nice to have, power is even nicer to have. Force is a bit of a precursor to power. Two athletes can have the same squat and same bodyweight, but maybe one athlete can powerclean significantly more than the other, that athlete is much more likely to be a good accelerator. You see what I'm getting at? Force isn't enough, you need power. So I guess a question is, what are some of your "power stats" if you know them? Vertical jump? Power clean? Hang power clean? Jump squat? etc.

Starting is very technical and demanding. How often do you practice block starts? I have zero idea how often a good sprinter practices starts, I imagine a handful of times per week. You need lots of rest between these starts so you can exert maximum power and avoid too much CNS fatigue. Something like pulling a sled has very little transfer to starting from a standstill.

RE power: I don't really know any power stats, the closest I have to one is that I had a 315 squat disqualified at a mock meet because I jumped during my lockout, I've definitely got a teeny bit of explosive power in there. I could certainly get to training my power-cleans more though. You have a good idea of a benchmark for the power cleans I should work against so that i can say "good enough"?

RE technique: I have done maybe 200 starts with my hands on the ground in my entire life, and precisely 0 with blocks.

I don't know what a good benchmark would be for power cleans. I can tell you that I'm a middle distance runner and probably capable of running 23 low for 200. During the offseason when I was at my strongest, I was capable of hang power cleaning ~1.25x my bodyweight with decent form. From the floor, in an all out effort, I probably could have given 1.5x my bodyweight a scare. I'd imagine most sprinters who train the power clean are capable of at least this.

If you're going to be a sprinter, you need to learn to use the blocks and you need to practice with them often.

Why are you concerned about sprinting? Do you plan to race the 100 or 200 m? If so, there are lots of YouTube videos and Facebook reels of how to improve your start technique.

Here's a tip that will help you come off the line faster without necessarily getting any stronger. It's all technique. If you watch a tape of most novices doing a standing start for a 200 m rep, you'll notice that they take a very short stutter step at "bang." they lift their foot off the ground and put it right back down where it was before taking their first real push-off step. That stutter costs between a quarter and a half second. You need to preload your muscles so they are firing to push off at bang instead of having to load up first and then fire off AFTER the bang. If you aren't preloaded and moving at the B of bang, then you're more likely to lift a foot and put it right back down in the same spot.

No mate, I figured this would give me a leg-up (if you'll excuse the pun) in my ceramics class. Ah wait, no no, yeah I think I was planning to race it actually, I almost forgot.

I like the preloading note, that's super actionable

Your problem is probably because you aren’t naturally a sprinter. What distances do you race?

Literally none, I've only started running last year and only started focusing on distances under a mile over the past few months. My most recent mile was a 5:05, my 400 a 59. I figure if I'm running a 24.7 with almost no training and terrible technique this is probably where I belong.

Probably also worth noting I'm 190cm and 90kg, there are few runners taller or heavier than me at longer distances