She can get down from standing with ease
Then you don't need to lie her down in her cot, she can lie down independently on her own.
How is she generally (away from sleep time) at following your instructions? Can you practice simple instruction-following in your play? Games like Simon Says, mimicking and copying your movements, musical bumps. Even things like put your shoes by the door, put this breaker on the table, take this banana skin to the kitchen...
Once you have mastered basic instruction games (and you may already getting there) then make some of the instructions based around expected behaviour. Climb down off there. Do not stand on the chair, you might fall. Sit down to eat your sandwich, I would like you to sit here to have your drink, sit down please.
Don't do these things for her. It is important to give the instruction and have her follow the instructions where possible.
So once this kind of instruction giving ancient following is embedded in every day life, then apply it to bedtime.
Commit to never lying baby down again. Ever. Be it in the cot or on your bed, put her down standing up, tap the matreess, ask her to lie down. Do that every time.
So in the cot, you forget need to make her lie down, you just keep repeatedly calmly and patiently give her the instruction to lie down, tap the mattress and wait.
If she refuses point blank, then you need to work more with positive praise when instruction following in play. This us just about behaviour expectations.
If she follows the instruction happily, great. That's half the battle. She may well repeatedly get up, sit up, delay tactics and what not. It happens simply because she now physically can get up. So be patient, it's not a big deal. Just repeatedly give the instruction to lie down and tap the mattress. Praise every time she lies down.
Positive praise works you teach children to follow instructions. It's how teachers and nursery nurses wink their magic. Praise when she follows instruction in play. Give instructions regularly and don't do things for her. Then praise and be proud of her. It's great for self-esteem building 