Resolving imports before sending JS scripts to the browser - is it a good idea and how to do it using Express

Say I have a web page with a script that imports from 20 other scripts. I imagine that having to fetch these 20 scripts separately adds more loading time that fetching one giant script. Which leads me to the question : would it be a good idea to "pre-resolve" the imports on the server's side, creating a monolithic "linked" script (ideally ahead of time) that can be sent to the client in one go ? If not, what would the downsides / issues be ?

And if yes, well how do I do that with a NodeJS/Express server ? Are there any packages that already to that ?