We did the second time we had to sleep train after a regression and it definitely worked. It was probably worse for me than him the first 2 nights

I do. In my opinon they need to learn to self soothe and crying it out helps motivate that. I never let my daughter cry for more than 10 minutes before id go rub her back and try again. If she didnt stop after the third try (30 minutes) then id pick her up and cuddle for a few minutes before starting all over again.