Property/Column level access in Entity Framework Core

Question

In this question I asked for a way to achieve Property/Field level access in .NET 5. One idea was to do the magic in the EF Core configuration, so that only those properties are loaded from database the current user has access to. In the second step the empty property will the excluded from the dto using the JsonIgnore attribute with default condition. I've tried my best to implement the logic in the OnModelCreating hook of the context using a custom property attribute on the entity properties:

public class MyEntity : BaseEntity
{
   [IncludeForRoles(RoleNames.Staff)]
   public string InternalDetails { get; private set; }
}

public class MyContext : IdentityDbContext<User, Role, Guid>, IMyContext
{

   private readonly ITokenAccessor _tokenAccessor;

   public MyContext(
            DbContextOptions options,
            ITokenAccessor tokenAccessor) : base(options)
   {
        _tokenAccessor = tokenAccessor;
   }

   [...]

   protected override void OnModelCreating(ModelBuilder builder)
   {
        base.OnModelCreating(builder);
        builder.ApplyConfigurationsFromAssembly(typeof(UserConfiguration).Assembly);

        foreach (Type type in MyContextUtility.GetEntityTypes())
        {
            MethodInfo ignoreFlagMethod = MyContextUtility.SetRoleBasedIgnoreFlagMethod.MakeGenericMethod(type);
            ignoreFlagMethod.Invoke(this, new object[] { builder, _tokenAccessor.UserRoles });
        }
    }
}

public static class MyContextUtility
{
    private static IList<Type> _entityTypeCache;

    public static IList<Type> GetEntityTypes()
    {
        if (_entityTypeCache != null)

        {
            return _entityTypeCache.ToList();
        }

        Assembly assembly = typeof(BaseEntity).Assembly;

        _entityTypeCache = (from t in assembly.DefinedTypes
                            where t.BaseType == typeof(BaseEntity)
                            select t.AsType()).ToList();

        return _entityTypeCache;
    }

    public static readonly MethodInfo SetRoleBasedIgnoreFlagMethod
        = typeof(MyContextUtility).GetMethods(BindingFlags.Public | BindingFlags.Static)
            .Single(t => t.IsGenericMethod && t.Name == nameof(SetRoleBasedIgnoreFlag));

    public static void SetRoleBasedIgnoreFlag<T>(ModelBuilder builder, IList<string> userRoles) where T : BaseEntity
    {
        IEnumerable<PropertyInfo> props = typeof(T).GetProperties().Where(
            prop => Attribute.IsDefined(prop, typeof(IncludeForRolesAttribute)));

        foreach (PropertyInfo prop in props)
        {
            IncludeForRolesAttribute attr = prop.GetCustomAttribute<IncludeForRolesAttribute>();
            if (!userRoles.Intersect(attr.RoleNames).Any())
            {
                Debug.WriteLine($"Adding ignore flag for type '{typeof(T).Name}' and property {prop.Name}.");
                builder.Entity<T>().Ignore(prop.Name);
            }
        }
    }
}

The ITokenAccessor provides access to the jwt access token of the current user. The above code does not work because OnModelCreating is executed before a user is logged in and that's the reason why _tokenAccessor.UserRoles is always empty at this point.

Is there a way to achieve the property/column based access in entity framework core? I spent hours researching but unfortunately couldn't find a solution. And I am very surprised that property/column based access should be such an unusual requirement.