I read something once about it triggering let down (the nursing srtike thing being secondary to the slow let down thingy). But I think I read it was only prescribed in the period very shortly after birth.
I get the impression MB that you've tried all of the standard "condition your letdown" techniques from Kellymom etc, without much success. I really am scraping the barrel with this idea, and it may be wildly inappropriate. (Hence my worrying about tiktok disapproving of me proffering dodgy advice). I just wanted to mention it in case someone more knowledgeable thought it genuinely might be an option (even for the placebo effect, perhaps!).
The only other thing I can think of, MB, is this...
When babycarrot has nursed to sleep and stayed latched on, I sometimes get another letdown after she's asleep and not really sucking any more. I've got into the habit of whispering "milkie coming, babycarrot" when the letdown starts, and she stirs enough to get sucking again.
I still feel random letdowns throughout the day, when I'm pottering around the house. I don't leak or anything, just feel them happening.
If I was to grab her when I feel one coming on and get her on the boob quickly, perhaps with the "milkie coming" phrase, I'd get a quick opportunistic feed out of her.
Would that work for you? Do you still feel letdowns when you're not nursing?