A friend of mine had this problem with her 5mth dd. Her dd was always unhappy, couldn't be given to anyone to hold, would only fall asleep in a sling and wake at night and take hours to resettle. Hated buggy too.
They tried hair dryer, hoover sound, car seat, walking for hours, etc
At the end of their tether, they had a sleep specialist come for 3 days and at end she settled herself in cot in day and at night. She was immediately much more happy and gurgly. I don't think I had really seen her dd smile up until then.
This is gist of what she did over the weekend. (don't shoot me down, just giving the info!): Don't let dd sleep in in am's. Think they were aiming for short nap mid morning and two hour sleep early afternoon and sleep through night with feed if required but that dd would be put in bed awake and settle herself to sleep.
When should be awake stimulate her with toys and keep her awake until you want her to nap. When she should be asleep, persevere with them in cot, by what ever means i.e. going in soothing, stroking but don't pick up. Once nap time over (whether sleeps or not), get dd up and keep awake until next nap/bedtime.
Apparently, the first over night was dreadful and she was awake for most of night but from next day, she has pretty much slept and settled herself (with a few blips!).
Her dd is now always happy, smiling and her parents obviously feel more human and think that one night, although horrible, was worth it.
I think they also established that dd liked to sleep with something half covering her face as it would be in sling against her mum. So she was given a light blanket up high over her chin - loosely!
As I say, only giving info, not saying whether you should do this! Not sure I could have stood it all night but then I was very lucky that my 2 dcs slept well day and night - but then I was paranoid about not feeding them till they went to sleep or holding them when asleep. Not sure if that made any difference though!