pbjs -w es6 will generate an import statement that simply fails, because it's ES6 not CommonJS.

It can't import a file with the extension omitted, it has to import "protobufjs/minimal.js".

Or an "exports" field entry for /minimal needs to be added to protobufjs to make it work.

https://nodejs.org/api/esm.html#import-specifiers