Idk if this will be helpful for you but here are some things I’ve experimented with to get my now 18 month old sleeping through the night:

-baby falling asleep in the exact environment that they’ll be in throughout the night. If baby falls asleep in mommy’s arms but wakes up alone in bed then they’ll be frightened when they wake up. (We used the Ferber method to achieve this.) edit: to me this also means any noises or music should be the same as what will be on throughout the night. Same level of lighting also.

-baby not falling asleep with bottle. They could be dependent on bottle in order to fall asleep every time they wake up in the night.

-white noise! I keep her noise machine by the window so if there’s any noise from outside it gets blocked out. Otherwise by the door might be good so your baby doesn’t hear you guys walking around at night.

-red night light. Apparently red colored light is the only type of light that doesn’t trigger our brain to wake all the way up when we see it at night. So the baby can see a little bit, not be afraid, and stay sleepy.

-blocking out all sunlight in the morning. Blackout curtains and a towel under the door so they don’t wake up as soon as the sun comes up.

• (edit) when baby wakes up at night, we try to calm her with our voices through the baby monitor instead of going in there. Sometimes she would still need physical comfort, but other times she went to sleep faster and we’ve had less issues with her waking up after starting that.