2 year old has never slept through the night....

I have a 2 year-old and I can count on one hand the number of times she’s slept through the night. I work full-time and find myself dozing off during my commute (45 minutes one-way). I have tried everything but nothing keeps her asleep all night. Bedtime routine starts at 6:30 with warm milk, bath at 7, all lights are turned down low and we start reading at 7:30. I lay her down at 8. She will wake up as early at 10:30 and as late as 4 am, no consistency. One she wakes up she won’t fall back asleep until she’s in bed with us. We’ve tried sleeping training with a modified version of crying it out 3 times. This is the 4th time. I stay in the room and put her back in the toddler bed every time she gets out. The 3rd attempt got her asleep in 15 minutes but didn’t stop the night wakings. Co-sleeping is not an option because she takes over and I end up sleeping in weird position and with backaches because she false asleep by caressing my ear and that means I can’t moves. I’ve tried substituting with a scarf or soft toy but she won’t go for it. Right now she cries on and off for an hour before falling asleep. Any suggestions? I’m willing to try anything. I’m starting to get horrible headaches and I just can’t do the night wakings anymore.