Greetings (I live near Paris and speak french natively),
I am proefficient in fullstack deployment, both front-end (react, Vue) and back-end (node, prisma, django). I see you have mentionned Django in your tags, which I also use, is that a requirement?
Otherwise, I would probably suggest using a GraphQL server as it seems to fit a lot of your need for flexibility and fast prototyping.
I really like this approach of prototyping and providing a minimum viable product as soon as possible, and adapt with feedback over time.
I am also acquainted with data visualisation and machine learning.
However, to provide a full bill, I would need to know some informations that are missing: What is the end product supposed to be like? What are the criteria that matter to you (usability, speed, security, correctness, flexibility, etc...)? Would it be a fixed time allowed for the project?
If you are interested, please drop me a message with more details on your project and how we could work together.
I wish you luck in any case!