My guess would be React/Angular or, if it's a particularly hip group, Next.js/Nuxt.js/Serverless with as little back-end as possible.
For backend, graphql is in, expressjs is still in, firebase is in, flask and django are in.
Ruby on rails is unfortunately out among my peers: https://devpost.com/software/built-with/ruby-on-rails
Not a bad idea to do a blog post analyzing devpost trends, I might do that after exams.
My guess would be React/Angular or, if it's a particularly hip group, Next.js/Nuxt.js/Serverless with as little back-end as possible.