The new bathroom radiator simply does not get warm

Hello, that sounds like a tricky situation. Maybe there is still air in the system, even if you have bled the [Badheizkörper], then a complete bleeding could help. Also check the system pressure again to see if it remains stable at 2 bar. Sometimes the valves may not be fully open, or the circulation pump does not deliver enough pressure. There may also be deposits or blockages in the pipe that obstruct the water flow.