Can you put the cot in a different room?
My dd did this when she went through sleep regressions. If it was before 5am I would persevere with putting her back down in her cot (was in a different room)
So I had a little routine.
1st time of getting up go in, say its bed time now, lie her down and sit on the floor with my head in my hands.
If she got up again, would say "bed time" and lie her down. Sit on the floor.
If she got up again I wouldn't say anything and Just lie her down. This would then be repeated until she settled .
I would have to do the same routine for actual bed time. I would always sit on the floor and not make eye contact even if she was trying to get my attention.
Wont deny on a few occasions I would hold her hand through the cot bars and/or sing gentle songs .however after about a week or so this would work until the next regression or disruption to routine. But she would take to the process alot quicker each time.
If it was after 5am I would generally put her in our bed as it seemed futile to do the routine just before waking time anyway and it meant some of the time I could doze.
Now she is 2.5 and since going into a cot bed has been alot better and if she does get out of bed will go to sleep after one return (most the time 
)
When we did take the sides of the bed and even now there is a gate on her door so she cant sneak into our room. This is mostly cause dh has night terrors and I worry about his reaction if she just appeared in our room.
It took perseverance and patience though to get through this stage and was about 9 months before she settled most nights without fuss.
I do remember sitting on her bed room floor in the middle of the night counting slowly and thinking about breathing so I didn't lose my shit.
I have also let her cry it out a few times when I lost all patience as this was better than me getting upset and wound up.
Good luck OP.