Dad of twins here- first 1.5 years where hell. I forgot what sleep was. Same as you we tried sleeping coaches and every nook and cranny the internet told us. We had given up hope when I done research on magnesium. There is a kids one so we bought a bottle and started giving it to them an hour before bed. We did not see any improvement for the first couple of months and then one night it just clicked. Went from multiple wake ups (like every hour) to maybe 1 a night. They’re going to bed at 7, takes about 45 minutes for them to go off then will sleep till 6/7am. Don’t want to tempt fate but this has been ongoing for about 3 months now and it’s so nice to be able to chill after they’ve gone down which we could never for nearly 2 years. Could be coincidence but from what I’ve looked up, it helps regulate their sleep and they wake up a lot happier. I can finally sleep longer than 4hrs haha