You have not failed your daughter. You did all of this because you love her and because you've put her needs above yours. That makes you a great Mum doing her best x
OK - There are loads of different ways to move forward from where you are and make sleep better for you all. The first thing to do is have a think and make a firm decision on how you're going to tackle this. A scattergun approach rarely helps. You need A Plan.
There are no better options or worse options here. Just different options. Which most feels right to you? ....
Cosleep more comfortably
I kid you not, buying a super king sized bed has been one of the best things I did after having kids. And we don't cosleep (kids just pop in in the morning).
An option would be to buy a bigger bed. Don't go half measures with a king sized, go whole-hog with a super king! Then carry on cuddling and stop stressing and get better sleep.
Sidecar Cot
A half way house between cosleeping and own room. Without the expense of a new bed. Bring DDs cot into your bedroom, remove one side off it (easily done with all flat pack cots) raise the matress height to match yours and butt it up to the side of your bed.
This allows you to cuddle DD to sleep, but in her own space and it allows you to extract yourself into your own space once she is asleep. The sidecar cot can also be used as a gradual transition to independent sleep - So no assumption you'll be sharing a room for the next few years.
Independant Sleep - Slow and gradual
Accept there will be tears in doing this. But you stay with her and comfort in the cot. Stay being caring and compassionate, but with clear boundaries that she will be going to sleep in the cot.
By staying to comfort her at all times, you need to be able to stay calm and not get agitated or cross at her tears. She will cry because she wants to sleep and doesn't know how to do that in the cot. Do stay calm and caring while she learn.
It's a long process. Start off with bending into the cot all the time, cuddling, hand on chest patting, other hand close to face, your face as close to hers as possible. Keep lying her down. Just keep going.
Over time the amount of reassurance she needs will reduce at your DDs pace. So without pushing her she will gradually get used to it and it will get easier.
But this is no quick fix. She's likely to need your help to go to sleep in the cot for many, many months to come. You will need to be consistent, because it'll be confusing to her if sometimes you insist she sleeps in her cot and at other times you're too tired and just bring her into your bed instead. Be it 2h to settle her at 7pm or that call at 2am - you need to be prepared to continue the consistency every time.
Independant Sleep - Harsher but faster
There are reasonable arguments that it is easier on children (of over 12 months) to not have the prolonged distress in learning to sleep independently. So do the teaching over the space of a few days, not many months.
There are various approaches to this. It might be that you go in and comfort baby, leave for 2 minutes and then go back, and keep repeating. It might be that you stretch the time you're out of the room.
It might be that instead of leaving baby alone to cry, you stay with her to comfort, as described above. But instead of pacing the changes to reduced comfort at a pace set by the child, that you control that journey toindependang sleep. So the idea is that you do a few dats of a certain level of comfort, then a few days of less comfort, and so on.
Step One to solving this is deciding HOW you are going to solve it