Which framework is better for building UI?

Hi there. I’m very new in Unreal so I’m sorry in advance if my question seems strange. I’m panning an application with a pretty complex interface for interaction with a remote database. I want to choose proper way for building the UI, choosing between Slate and UMG. Also, since the interface is already built on web-based platform, can it be a solution to add a browser widget and keep the UI web-based? So to summarize: which of the 3 methods will be the best for creating UI? Thanks in advance.