Sounds very similar to my son. Would fall asleep in my arms or in the sling, but not by himself in bed, and would never sleep longer than one sleep cycle during the day. I even used to have to sit on a fit ball and bounce him to get him to fall asleep.

We tried all the "tricks" but it just seemed to be his personality. I also liked the snuggle time, even when he was in the sling

Without changing anything, over time his sleep patterns changed. He eventually started sleeping for 1 1/2 hours for some of his naps. But he fed 2-3 hourly around the clock until he was about 16 months old. Then the night feeds went down to 2-3 per night. Eventually it was like a switch clicked and he slept through one night and has been doing it since. He was 19 months old when that happened (the month before my daughter was born). It's now very rare for him to wake at night and he sleeps from around 7.30-8pm until 7.30-8.30am.

The reason I think it's a personality thing is because we have done everything exactly the same with our daughter and yet she is a great sleeper! She has very strong tired signs and a very distinct tired cry. As soon as she even seems tired we can pop her down wide awake and she goes off to sleep without a fuss. She still feeds 2-3 hours around the clock though, but she's a nice easy night feeder which helps.

I know things must seem hard now, but fingers crossed that things will improve without you having to do much. Something that really helped me when I was waking lots during the night with my son and not getting a rest from day naps was remembering that's it's not like I was waking and having to go and shovel snow from my driveway. I was waking to have cuddles and precious breastfeeding time with baby. Sure, there were times when I got frustrated and thinking about that didn't stop me from wishing we were both asleep, lol, but I definitely found that I felt less tired once I stopped worrying about the lack of sleep, and just sort of accepted it as my son's way of life