I don’t see much difference either. In fact, this should lead the team. Your code organization can be useful if you have separate front-end and back-end commands. I saw the environment when the user interface only loaded part of the user interface and connected to the REST server deployed somewhere on the DEV server.
Number 2 is the release procedure. If your external interface and back panel are tightly connected, they will be released together 99%. Then you do not need to process 2 repositories. However, if your back-end will serve as the endpoint of the REST service for other clients, not only your user interface, and you plan to release interface changes without touching the internal ones (without downtime for external clients), you may want to use two separate repositories.
CI. , . CI , , .