I think a major factor of deciding on a package is how the final application is distributed to the user.
If the users already have Julia installed, I’d probably go with Pluto.jl and PlutoUI.jl.
If users would have to install Julia first I’d instead opt for a web based application. I’ve had good experience with Dash.jl, but there is almost no default styling so you would have to write at least some css. I have no experience with Stipple, so I don’t know how it compares.
In that case you probably can’t go wrong with a Pluto notebook. The UI bindings are super easy to work with and you can use your favourite plotting library.