What ways have you found are successful to win against legacy incumbents as a newer technology that may have some feature gaps?

No product has all the features, but barely people choose products because of one specific feature.

Find out what the prospect really tries to solve with the legacy incumbent and what they are currently struggling with. Sometimes it takes time and effort to really find out the pain points because people got used to them and see them as unchangeable.

Build up a story on where they will be like in 1-2 years with your products instead of sticking to the existing one. Make them want this future and explain why only you can build this future.