Baby sleeps better in our bed than crib...

I’ve noticed my baby will sleep in longer stretches on our bed during the day (we are awake and watching him) versus at night in his crib he will wake up every half an hour tossing and turning. I don’t know if his crib is too firm but he loves our bed waaaay more than his crib. Even when my mother watches him she put him on her bed and he sleeps for hours there yet will only sleep for about 30-40 mins in his own crib. Should we get him a different mattress? Has anyone come across this issue? We got him an extra firm mattress but now I’m starting to think maybe it’s too firm for him. He slept fine in it when he was a newborn but when he turned 3 months a month ago he started not sleeping comfortably in it.

Or is this just him getting older and having more of an attachment to us?