My Macbook 12 inch has a wifi problem.

I have a Macbook 12 inch 2017. I recognized a Wifi problem recently. I tested this problem many times and it is always the same.

1) While my Macbook is connected to 5GHz wifi, it drops after 2 or 3 minutes. It shows it’s still connected, but internet is actually not working at all.

2) Problem on 1 above can be addressed by connecting 2.4GHz wifi, not 5Ghz. But this also drops after 40-50 minutes of use. It shows it’s still connected, but internet is actually not working at all.

3) Many devices (laptops/smart devices) are connected to my home router, and this problem occurs only on this Macbook. So I assume that it is not my router/internet problem.

4) I tried several things already and nothing changed.
-System Preferences -> Network -> Advanced -> TCP/IP -> Renew DHCS Lease -Pram reset -SMC reset

Anybody can give a help or experienced the same? Thx