Internet connection drops every few minutes (Setting BTCoex Config)

MacBook Pro (Retina, 13-inch, Late 2013)

I can only notice this while watching videos, because Youtube video player crashes every time this happens. I feel lucky if I can watch some show for more than 20 minutes.

In the Console, I see this message every time the youtube player crashes:

Setting BTCoex Config: enable_2G:1, profile_2g:0, enable_5G:1, profile_5G:0

What did I try so far?

• I had MacOS catalina. I installed Big Sur but the problem persists.
• I disabled 2.4ghz on my modem and use 5ghz only but this also didn't solve it.
• I used a different modems no luck. If I see that message, my connection is refreshed somehow.

I have another MBP (2015), it works perfectly.

Is this a known bug? Do you know what is this BTCoex about? How can I disable it?

Thanks