Have you tried the wonder weeks app. Babies generally have a few regressions, at 4 months, 6 months, I cannot remember after that.
My first was a terrible sleeper, even in his own room. Still only naps for short periods, but now once he's asleep at night he generally stays asleep. He's now 2. I ended up having to go through a sleep consultant by 6 months as I couldnt handle it anymore. It may be something worth considering, even just for the advice.
I'd been against the cry it out method until I was so sleep deprived that it was getting rediculous, bit each to their own, some people will agree, some won't. It worked for our son, but the first few days of sleep training were hard. Being my first, looking back I should've got assistance sooner.
My 2nd at 7 months is still in our room, an excellent sleeper, however he has epilepsy and is on medications, and the side effects can be tiredness, so I do wonder how good a sleeper he would be if not on medications. He had been in his own room, but moved back with us due to his epilepsy, much to hubby's annoyance, more because he gets up at 4am and is afraid he'll wake him 
Every child is different. I ended up having to take our first out of our room at 1 month old. Both he and his dad snore, I couldn't handle it. He now sleeps with white noise in his room, which helps him to sleep.
Things to consider.
- Is your room dark, this can affect quality of sleep for bub if room is too bright. I have blackout blind against the window with suction cups to block out light.
- How noisy/quiet is it. My babies tend to wake more at night without white noise, as the area we live in is noisy during the day, but quiet at night.
- How hot/cold is it, this can affect sleep.
- Method of how bub goes to sleep, are they rocked, patted or just left to it.
- Do they need to cuddle up to something when they sleep.
My 1st never needed any comfort toy, but my 2nd from day 1 needed to hold something and have a dummy/pacifer. He now cuddles up to his bunny to go to sleep, but each child is different.
No judgements here, it sometimes take trial and error to work out what will work for you. You may need to try a variety of methods until you can find what works.