FP3+ Black Screen, Looking for Battery + Screen

Hello,
I have a problem with my fairphone 3+. It was working well, until it completely went unresponsive. I have

  1. Open and clean following Vue éclatée du Fairphone 3 - iFixit up to step 7.
  2. Let it charged over the night
  3. turn on with volume button

However, nothing seems to work. Could someone in Zürich (or Switzerland), who has a FP3+, let me test if it is the screen or the battery issue? I really do not want to buy another brand new phone, it is not the goal of it.

Thank you in advance

There are angels in Zürich, contact them via e-mail maybe they have a FP3 to test. Infos here fairphoneangels