Personally, I converted our in-house Flask app to a RoR application with View delegation to React. This was mostly to align the technology to the skills we currently have on the team, but I got a lot of experience in the process.
See if there is any room to convert your current Python applications to Ruby.
Working on a new production app right now that does not use Redux, I do not plan on backwards integration either. For reference, our team does have two applications that utilize Redux.