Messed up nutrition for the last time

Alright. Seriously. How the heck do I not bonk? Off the back of a miserable 70.3 Madison run and 2ish hours in the med tent after while I got over nausea and chills... I think I've humbled myself enough after 12 years of similar results.

My buddy joked this year that he knew I was in the bad place by the look on my face on mile 8 of the run. I barely even notice going there now because it seems like every time. I just live in the bonk zone on the second half of these runs.

I think I've ruled out fitness as the cause. I put in the work. 1-2 hours most days, long bricks, off season work xc ski racing with my maintenance work. Engine is not the problem. I can pretty easily sustain good speed on the bike, taking it super chill on half and full IM distances, and have raced enough times now to execute a race plan into run. I eat and drink carbs like crazy, swallow my salt pills, and have a couple of snacks to settle the tummy. I drink enough to have to pee a bunch on the bike and run. Ive tried everything except the mail order nutrition thing.

Im looking for feedback on the whole "performance fuel and hydration race plan" schtick. Does this shit actually work? How about the competitors? Do you just pony up the money? I figured the carb load and salt levels, but I continue to drop time at the end of these races. Should I abandon my stubborn rejection of mass marketing macros and give in to my capitalist triathlete overlords?

I get this is a coach convo (and believe me, im having it), but looking for your unverified internet vignettes, as is tradition!

Help me Obi-Wan Kenobi, youre my only hope. Thank you for your attention to this matter.