Dynamically paging EF Core results

Question

I have a UI grid which permits sorting by column :

Id	Organisation Name	Organisation type	Departments
1	first	some type	def
2	second	another type	abc, def
2	third	some type	xyz

See the entities below:

public class Organisation
{
    public int Code { get; set; }
    public string Type { get; set; }
    public string Name { get; set; }
    public List<Department> Departments { get; set; }
}

public class Department
{
    public int Code { get; set; }
    public string Name { get; set; }
}

I want to be able to sort the table values by Departments which is a comma separated values that comes from Organization.Departments.Select(p=> p.Name); I would like to make the sorting as an IQueryable and avoid bringing all the data in memory because After sorting I will apply the pagination and I don't want to bring all the DB records in memory.

I'm using the following extension method for sorting, but it is not working for nested collections:

public static IQueryable<T> OrderBy<T>(this IQueryable<T> source, string sortProperty, ListSortDirection sortOrder)
{
            var type = typeof(T);
            var property = type.GetProperty(sortProperty, BindingFlags.IgnoreCase | BindingFlags.Public | BindingFlags.Instance);

            if (property == null)
                throw new OperationFailedException($"Sorting by {sortProperty}");

            var parameter = Expression.Parameter(type, "p");
            var propertyAccess = Expression.MakeMemberAccess(parameter, property);
            var orderByExp = Expression.Lambda(propertyAccess, parameter);
            var typeArguments = new Type[] { type, property.PropertyType };
            var methodName = sortOrder == ListSortDirection.Ascending ? "OrderBy" : "OrderByDescending";
            var resultExp = Expression.Call(typeof(Queryable), methodName, typeArguments, source.Expression, Expression.Quote(orderByExp));

            return source.Provider.CreateQuery<T>(resultExp);
        }

This method works fine for properties that are at object level.

IQueryable I'm using later for sorting looks something like this:

var iQueryableToBeSorted = _dbContext.Organization.Include(p=>p.Departments).AsQueryable();