LO wailing all the time when trying to crawl

My 2.5mo has recently learned how to roll back to tummy, and will then proceed to kick himself forward using the railings until he reaches the end of the cot. Its obviously very tiring. And when he gets tired, he starts crying. If I rescue him and flip him back he immediately rolls back, or gets annoyed and wails. If I grab him up and soothe him, he struggles in my arms and wails. And when we put him down again he will roll or cry because apparently he hates being on his back now. It only stops when he is so tired he falls asleep after a crying bout. I get it is part and parcel of his learning journey, but has anyone encountered this and what do you do to help him? When the baby cries is it just out of exertion and we should leave him be, or does he need to be rescued - if so why does he still cry? And does anyone's LO eventually learn to flip tummy to back? My mom insists that's not a thing and babies only do back > tummy > crawl. #1stimemom #firstbaby