First I would move all of them to golang (unless you need ML/data science which is python). Next, I would create microservices using GRPC and define an interfa

First I would move all of them to golang (unless you need ML/data science which is python). Next, I would create microservices using GRPC and define an interface between them, this way they can continue working on each stack (and you can replace it in future date). I assume that if you choose a unified stack there will be a rewrite which is risky.