iPad Air 2 4G to WIFI – Weak signal after IC replace

I replaced the WIFI IC on a 4G model Air 2 to convert it to a WIFI model. Despite some issues on the way I managed to make it work, but now it has a lack of wireless sensitivity. Where the iPhone has enough WIFI signal, the iPad doesn’t or has a very high packet loss.

If i stay near the access point I have no packet loss. I have a circuit diagram and I can read it but nothing came to my mind yet.