9mo won't sleep in cot at all - cries as soon as put down

[MumOfCub2019]

I'm a first time mum of a very willful little girl. We've been cosleeping since she was around 3/4 months and would no longer sleep in her next to me crib, though feel it's time for her to have her own space. We would have liked to get her in her own cot/room from around 6 months, however due to a mix of the pandemic restrictions and being messed around by an online company, we've only had her room ready a week or so.
We're trying to get her into her cot, both to give her somewhere to nap and rest peacefully, but also to give us some space during the night (she's a bed hog!), however she just will not go to sleep in it.
She's always been clingy (made worse due to being stuck with just me for months during the pandemic) and either breastfed or rocked to sleep, and once she's sleeping I can get her onto our bed by putting her down on her side laying with her. She sleeps on her side/front and wakes up instantly if put on her back. However when we try to put her in the cot, even if she's heavily asleep, she tenses as soon as I go to move her and is crying before her head touches the mattress. Full on meltdown tears, snot bubbles, and it starts to sound like she's gargling her own spit which makes me worry she'll choke. We tried two hours last night and it got worse and worse, and we've yet to successfully get her down for even a small period overnight. She either lays on her back wriggling and wailing, or sits herself up and does the same. She only stops when picked up and cuddled (by me mostly)
During the day we put her in to play, and she seems happy enough so long as we're in the room (ie she doesn't panic) but we have the same reaction with trying for naps.
I'm at my wits end trying to get her in there, even after only 4/5 nights of trying - it's just getting worse and no glimmer of hope. She's just started crawling and settling in at nursery (where she also won't sleep) so I'm desperate to nail this - any help would be so, so appreciated
We've tried white noise, lullaby sounds, a diffuser, pitch black, little nightlight, singing, silence, rubbing or placing a hand on her tummy (can't rub her back as she won't turn at all), even putting a breast pad under the sheet to make it smell of me. The only other thing I can find suggested is controlled crying, but I can't bear to hear her cry for so long, she just doesn't console herself. I feel like I've done everything wrong up til this point and no idea how to make it better

(sorry for super long post!)

[FourPlasticRings]

You'll be fine, don't worry. You've not done anything wrong. It's a big ask for a baby to sleep on their own- many adults don't like it! She'll adapt when she's ready.

What I did was start with naps. I'd wait until she was asleep, count eight minutes and transfer to the cot. She'd often wake immediately, and then I'd pick her up and cuddle her the rest of the nap, trying again the next nap. I always got her immediately upon crying and eventually she seemed to grow to trust that I would come for her so she didn't need to feel anxious about being left. We then started to transfer her to her cot at night until about ten p.m. when I brought her into our bed at the next wake. She eventually started sleeping 6-10 in her cot and then moving in with us. We got her an actual bed at 18 months and she started sleeping through around then- she really didn't like the bars. We did then have a regression at 18 months and another at 2 years but now she's in her own room all night most nights.

Good luck!

[NewtoHolland]

The no cry sleep solution has some good tips for helping transitions like this xx

[cheeseycharlie]

Sympathies OP. Helpful ideas from PPs.

I did controlled crying. The insight I got is that some babies do just cry as they put themselves to sleep. The 'controlled' bit in the name is really about controlling yourself not to just pick them up when they cry, to allow them to learn how to self soothe and get to sleep independently. Which is a really important life lesson!

I learned through this that there was a definite pattern with DC1 who would wail at increasing volume before conking out. So when I previously was picking her up to soothe her I was actually waking her and stopping her from getting to sleep!

DC2 wasn't the same and he was very clingy and would fight sleep very hard. But I felt it was important to train him to sleep in his room without me.

[MumOfCub2019]

Thanks for the suggestions. We've tried nap times today but she's now in a full meltdown
@NewtoHolland how does the no cry method work? All I can find without buying the book is to remove the reliance on feeding, but I feel like we're doing that, just she's wary of the movement to lying in the cot