ASP.NET Core how to change policy requirements based on user selection

Question

In my Blazor webassembly project I can see all roles, delete and add new ones. I can also assign a role to a user and authenticate the user based on that.

Now I have for example my RolesController.cs:

// GET: api/Persons
[Authorize(Policy = "SeeAllRoles")]
[HttpGet]
public async Task<ActionResult<IEnumerable<IdentityRole>>> GetRoles()
{
     return await _roleManager.Roles.ToListAsync();
}

// GET api/<RolesController>/5
[Authorize(Policy = "GetRole")]
[HttpGet("{id}")]
public async Task<ActionResult<IdentityRole>> GetRole(string id)
{
    var role = await _roleManager.Roles.FirstOrDefaultAsync(r => r.Id == id);
    if (role == null)
    {
        return NotFound();
    }
    return role;
}

Every controller has a unique policy for each action. So that I can restrict each action individually. Normally I would just define the policy in Startup.cs, add .RequireRole("Admin") or something to it and now every user in this role would have access to the policy I specified.

To the question: I want to have a list of roles, as I have now, with the ability to select which policy should be included in this role. So that I can login to my application go to Roles and add a new role NewsDisplay and only select policies necessary to view the news feed. Then I can add users for my various displays and put all of them in the newly created NewsDisplay role.

I guess this is possible but can´t find a sufficient solution to this. Would be nice if someone could give me examples, links, ideas.