Well IMO that's just a very negative view on your own state of affairs. You might just think it's being realistic but slow clunky people can become fast athletic people with smart training and commitment. I've seen it, others here have seen it, fuck, adarq himself was a slow-twitch long-distance guy before he started training for vert. There's plenty of examples and you haven't really given any convincing reason why you CAN'T be like that as well. Why not just change your journal name to 'chasing kingfish' then?
I'm sure you'll think I'm being naive and you seem pretty set in your opinion on this but there's no logical reason to hold self-limiting beliefs when it comes to athletic training. Every other aspect in life you need to be realistic, but not training. No one is going to laugh at you, you've literally got nothing to lose except realising what your actual potential is. Most people don't even scratch the surface.

i don't do RVJ but that doesn't mean im plyo deficient. i do so many volumes of low-mid intensity jump drills using jump ropes and hurdles. those + the actual SVJ drills.
i consecutive double leg jump 36" hurdles 8-12 in a row. those are my favorite aside from the 2-hand SVJ dunks.
even simple 1-min set of single leg jump rople drill (front to back, and side to side) will get you stiffer in just a couple of weeks of doing them consistently.
strong plyos eventually boost your squat too.