HowTo decouple/separate Front- and Backend?

[capsloq]

There are use cases in which you might want to decouple the front and backend to use a different backend, not the on in this project.
Provided that the other backend implements auth routes, callbacks etc.

Is it possible to have a minimal frontend version including appbridge, which can be started on its own and connected to a backend url?
I did some rudimentary testing by starting cd ./web/frontend && yarn dev only the frontend and injected an API Key into the vite.config.js manually. Also i added host query parameters manually, e.g. http://localhost:3000/testpage?host=Y2Fwc2xvcS10ZXN0LTIubXlzaG9waWZ5LmNvbS9hZG1pbg. Which redirects to the Shopify Store with the installed App. However i am not able to see the content of any pages from there. It says "content not found".

I am not too keen with vite and its config, so has anyone done that and could give some insight?
Thank you