I would say cot to
Dd went in her cot quite early and to help her we put her basinette basket in the cot for a few sleeps - she looked way to little in the big cot without it but yeah she moved around so much that she was much happier in the cot. Maybe also time for a sleeping bag rather than swaddle? Dunno but might help if he can move a bit easier??
Good luck! it harder for us than them!