Bluetooth hardly working after repair

Hi everybody.

I would like to ask a question about bluetooth connectivity with the Pixel a 5G..

I very recently repaired my own Pixel phone (screen and usb charging assembly had to be replaced due to damage), and I followed the iFixit repair guide as best I could. Everything went great, my phone is (almost) like new. Or so I thought, because I realised today that bluetooth connectivity is greatly reduced.

As an example, I have a bluetooth headset, and it wouldn't connect to my device as it used to before the repair. After a few tries I came to understand that my device now has a bluetooth range of practically zero. When I can establish a connection between my phone and the headset, I have to keep the phone in very, very close range otherwise, the link wil drop because the headset cannot find the phone anymore.

So I guess my question is : has anyone ever encountered a similar situation ?

I suppose that I didn't put everything back together as I should have, but what exactly ? The Wi-Fi works perfectly fine, and I have no trouble placing calls with the phone. Is it just the antenna that isn't properly secured. If so, why is only the bluetooth impaired and not the Wi-Fi ? Or did I damaged something else during disassembly and/or reassembly ?

If I have to open my phone once more, I want to be sure that the antenna is really what needs to be fixed in order to restore proper bluetooth connectivity.

Thanks in advance.