Gosh you poor thing. Another suggestion- have a good think about how you want her sleep times to go down, and start to role play that scenario with her using a favorite doll or teddy. My little one is a similar age and I won't say she consciously manipulates me, but she does seem to be exploring what works for her ( which isn't always what works for me!!) I think at their age the role playing is something they really get and then you can use that experience to refer to at her sleep time. You can also say things like "teddy isn't crying because he knows he is tired and needs to sleep" etc.
Also send the dolly or teddy to bed with her and when you go in to resettle her if she won't settle, then resettle teddy/dolly first, talking gently to it- it may distract your DD from the tantrum.
A cold turkey option is to get your DH to do the settling for a while? Maybe not as gentle as above but could break the cycle.
Good luck. Hope you find something that works for you.