Do you think that for such case, I mean choose a model then a script to apply on it, there could be a mechanism. Locally I already use dynamic require from a text parameter and it works well, but on remote script I didn't manage to make it work. Maybe is there a way to run a script from a remote folder ? or a way to require an url ?
No matter what you try, a website cannot 'dynamically' load resources (scripts) from other external websites. There are many things that will bite you if you try. Browsers execute in a very tightly controlled work space, and only user interactions (drag and drop, etc) allow access to external resources. Everything else has a fence around it.
The www.jscad.xyz website allows the use of hash (#) and query (?) parameters to pass a URL, but that must be a URL to a single file. And, as you probably already know, there's a backend piece that downloads the file, and presents it back to the website.
Sorry. But currently, the only way is to 'pack' all the pieces into a single file.