@SilvaPaulaD Thanks for your patience on this.
I have checked with App Service Engineering team and sharing the below.
This isn’t possible with the App Service provided FTP endpoint. The App Service platform supports FTP primarily as a mechanism for deploying website content onto App Service. As a result, it isn’t built as a generalized FTP-as-a-service offering with concepts like per-folder ACL’ing.
Feel free to reach back to me if you have any further questions on this.