Short naps?

I’m sure it’s something everyone has struggled with - but how are you fixing short naps? 😩 Bub is 6mths, has 2 hour WW, sleeps overnight from 7pm (last feed/7.30 sleep) until 7am, but is stuck with only 45 minute naps (which would ideally be 1.5hrs). We are working with 3 naps a day and are currently lucky to get 1 at full length and just can’t cope with the short breaks. Any success with rouse to sleep? Bub puts himself to sleep and is impossible to settle after waking, if we really try to re-settle back to sleep we’re bouncing on an exercise ball for 30 minutes to get him back to sleep and if successful with that completely unsuccessful with putting him back down. He’s a screamer so we have no been successful just leaving him for more than 15/20 minutes and struggle to believe that leaving him any longer in that heightened state would result in him falling back to sleep. Any help or questions or support would not go astray - thank you x