@Wishful I read that resistant starch is the fermentable part of the fiber,
I think it's more that regular non-resistant starch is digested/absorbed in the small intestine. Resistant starch and various other complex sugar molecules (hemicellulose, pectin, etc) pass through to the large intestine and colon, where microbes can break some bonds to access their food molecules, and while doing so also release other metabolites such as the short-chain fatty acids. Then there's non-digestible fibre, such as cellulose, which passes through without change (other than getting brown and stinky).
As an experiment, you can try some easily digested starches, such as cornstarch. Hmmm, I just checked and cornstarch is not the most easily digested. One list (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5223246/
) has the order (most to least) as rice, wheat, corn and tapioca, with potato as having about 200x more resistant starch than rice. If you really want calories without resistant starch, sugar should do it. Not great for satiation though.
It's surprisingly difficult to figure out which food is lowest in resistant starch. There's a lot of confusion about digestibility, with comments such as "resistant starch can't be digested by the body", which is false, since our microbes, which are part of our bodies, break it down into molecules that we can absorb/digest. Arrowroot flour is claimed as very easily digested, but it's also listed as being high in fibre, which might be resistant starch.
Another misconception is about fermentable fibre and glucose. While it's true that those molecules don't break down directly into glucose, part of it gets converted into propionic acid, which--if I understand this correctly--mostly gets converted to glucose in the liver.
I have the opposite of your issue #2. If I ate white rice in the afternoon, I'd wake up at 2-3 AM and be unable to fall asleep again. Here's an experiment: have sugar (zero resistant starch) instead of rice and see if that also creates the same insomnia. It would for me. You could also try running the cooked rice through a blender (smaller particle size should speed digestion). I'm sure that will also be less satisfying than regular cooked rice, but it's survivable as an experiment.
My most recent experiments have shown that I'm no longer as sensitive to the carb/insomnia problem as I used to be. I've been having cornstarch pancakes (without any supplemental fibre that I used to need) for lunch without having insomnia. I do seem to wake up earlier though; no more than 8 hours of sleep, whereas before I might have managed to fall asleep again for an extra hour or two.
As another experiment, if you aren't intolerant of meat, you can try going carb-free for a few days and see what happens. I'm thinking of trying that, since my proline sensitivity has declined.