In Entity Framework Core, is it possible to use a navigation property combined with backing field?

Question

Take the following entities:

public sealed class Employee
{
    private Supervisor supervisor;

    public long Id { get; set; }

    public long? SupervisorId { get; set; }

    public Supervisor Supervisor
    {
        get => this.Department?.Supervisor ?? this.supervisor;
        set => this.supervisor = value;
    }

    public long? DepartmentId { get; set; }
    public Department Department { get; set; }
}

public sealed class Department
{
    public long Id { get; set; }

    public long? SupervisorId { get; set; }
    public Supervisor Supervisor { get; set;}
}

And the following DbContext:

public class AppDbContext : DbContext
{
    public AppDbContext(DbContextOptions options)
        : base(options)
    {
    }

    public DbSet<Employee> Employee { get; set; }
    public DbSet<Supervisor> Supervisor { get; set; }
    public DbSet<Department> Department { get; set; }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        base.OnModelCreating(modelBuilder);

        modelBuilder.Entity<Employee>()
            .Property(e => e.Supervisor)
            .HasField("supervisor")
            .UsePropertyAccessMode(PropertyAccessMode.Field);
    }
}

When running the update database command:

dotnet tool run dotnet-ef database update

The following error is generated:

The property 'Employee.Supervisor' is of type 'Supervisor' which is not supported by current database provider. Either change the property CLR type or ignore the property using the '[NotMapped]' attribute or by using 'EntityTypeBuilder.Ignore' in 'OnModelCreating'.

How do I combine both the backing field concept and the navigation property concept? My goal is to allow the application to access employee.Supervisor and determine their supervisor if they have a direct report, or if they belong to a department use the department's supervisor instead.

I know I can add a new property to Employee named ComputedSupervisor with this logic, but I am trying to avoid having to refactor a bunch of code.

Thanks for any tips in advance!