[iamcalledrob]

It would depend whether the web app is a "dynamic website" or a "super interactive app that happens to run in a browser".

For a website, it'd be Go + HTML/CSS (sprinkling JS where needed). Here's why: (1) Code will "just build" years later (2) Deployment is stupidly easy -- just build to a single binary with all resources embedded (3) Everything about the stack is stable and easy to reason about. Though perhaps not exciting.

For a "web app", I feel there are no great options. The half life of the JS ecosystem is about 5 minutes, so whatever you start with will be out of fashion shortly after. React has had some staying power, though isn't without its flaws. I generally feel like most "web apps" could actually be websites though.