Hi,
So my advise is only my opinion!
I have two who have both been bad sleepers - one slept through at 14m and then other is just getting there at 18m. I tried sleep training with my first but not my second as I didn’t think it worked.
When they are ill or teething badly it is survival mode for you.
Othertimes you are looking for little things or little wins that will suit your baby. To me it sounds like you are doing everything right - trying to get good day sleep and plenty of day food.
For me there was no magic answer and I just had to keep trying things to see what suited my baby. The first used to want me in the room with her, sat on a seat near the cot - I did this until she was properly asleep and then crept out...this went on for ages and was very annoying but it eventually resulted in her sleeping through so didn’t need to do it.
My second woke more often. I substituted water for milk at about 14/15 months as I didn’t think the feeding in the night was helping. Then with him I just used to go in offer water and then put him back down with his teddy. If he cried I would pick him up (standing still) and then try again - this could go on several times. This seemed to work best for him as he wanted physical contact with me but I kept it minimum. He eventually slept through but gets up very early.
No one answer but I don’t think your baby is right for controlled crying. Trying something and it not working is fine cuz you are trying to work out what your baby needs.
At the same time you are doing a fab job - I have been there twice and it has taken me to my limits. That is fine - it’s really hard and anyone that sleep deprived would be the same.
Take in turns with DH (glad he is helpful!) to do shifts and then get in spare room if poss with ear plugs. You both need a block of decent sleep - agree this and stuck to it.
If it gets awful on the W.e each take her out for 2hr blocks and the other one sleeps/relaxes.
Go to bed every night very early - won’t be forever.
If it is really awful then take a days AL when she is at nursery and recharge.
You will get through it and you are doing amazing job - both of you :)
I think your baby will be a better sleeper in the long run if you work this through with her and she will trust you. My 3yo sleeps amazing now after being hell on earth for the first 14months.
This is only my take and I completely respect other approaches lol