Mine was exactly like this. Ours would cry unless she was constantly being held. We did the same thing you did and suffered for six months. DH and I had to take turns caring for her. We were out of our mines exhausted. We did a few things that helped. We downloaded an app called huckleberry and I don’t normally recommend subscriptions but in this case I recommend it. Get an age appropriate nap and sleep schedule from the app. Prepare anyone living in the home for a lot of unpleasant crying at night time. Get a comfy chair next to your baby’s crib. Also read up on something called sleep pressure because it’s an amazing technique.
Rather than trying to force your baby to fall asleep you are going to create something called sleep pressure by keeping them awake until they don’t have the energy to fight you. You might have to experiment for a couple of weeks to figure out the right amount of naps and how much sleep pressure is right for your baby.
When putting them down in the crib at night you can use the vanishing chair method if your baby still has a little fight left. But the sleep pressure should help tire them out. I recommend gently easing your baby in. On day one we enforced the first “nap” by putting her down in her crib while sitting next to her until her nap was over. I’ll be honest she cried the entire time. And then at night again for her sleep we put her down in the crib while sitting next to her for 15 minutes and then held her to sleep. Basically we were just trying to ease her into the idea of being set down in the crib at this point. So it doesn’t really matter if they cry at first.
Now is a great time to start a routine that will teach them “bedtime is soon”. for us the nighttime routine is
bath time
pjs
brush teeth
story and cuddles
the scheduling looked something like this…
Day 1
*wake baby up at chosen morning rise time (even if they didn’t sleep good last night)
*enforce first wake window. Enforcing wake windows creates sleep pressure. play with them. sing dance whatever you have up to to keep them awake
*Nap 1 in crib
(All other naps and wake windows are optional)
*Night sleep in crib 15 minutes
Day 2
Morning rise
Wake window 1
Nap 1 in crib
wake window 2
Nap 2 in arms
Night sleep 30 minutes in crib
Day 3
WW1
Nap 1 in crib
WW2
Nap 2 in crib
Night sleep 30 in crib
so on and so forth. Obviously you will have to read your baby’s needs a bit. But you will find the more you introduce the wake windows the better they will accept sleeping at night in the crib and just in general and have a more acceptable sleep schedule.
I would designate certain activities to each wake windows. Ours has 4 at this age. Cleaning for the first window. Then play time/tummy time and the third one a walk and then winding down for the last one. It gave our family structure but every family has different needs.