Method for Limiting Sites Using "Sites.Selected"

Background:

Currently, we are using the Graph API's "Search for sites" function to retrieve a list of SharePoint sites. Detailed documentation can be found here: Search for sites - Microsoft Graph.
In the future, we plan to implement site limitations using "Sites.Selected." However, the documentation for "Search for sites" mentions: "Note: This method does not support Sites.Selected
application permissions." Thus, it is our understanding that site limitations using "Sites.Selected" are not possible with "Search for sites."

Question:

We would like to know the necessary APIs to implement site limitations using "Sites.Selected." Please provide the following information:

• An alternative method for retrieving a list of sites to replace the "Search for sites" (Graph API). Additionally, please explain the authentication method required to use the API. (Should we use the SharePoint REST API instead of the Graph API?)
• The method/steps for applying site limitations. If there are multiple ways to do this, such as via API or web management interface, please describe all methods.