Question about ROG Strix Z690-A Gaming Wifi - 481251

Dear community, I have a question about this mobo. I bought it in February and, as is usual, I have just re-installed Win10. From the first day on, I had no internet access for about every 3rd boot. I have connected the board via LAN and the cable is always plugged in. At night, I disconnect the PC from the power supply via the main switch on a power strip. Since the problem with the unreliable Internet connection has now annoyed me enough, I wanted to set up the PC again over Easter to be able to rule out driver problems and the like. Now I'm sitting here after more than 24 hours and have the same problem again despite a newly installed Win10. Does anyone else have problems with this or even an idea what I could do? My specs, if needed: i5-12600k 32GB Corsair Vengeance Pro SL RGB @ 3200MHz, XMP enabled Asus GeForce GTX 1060 6GB Dual 850W bequiet Dark Power Pro 870 QVO Samsung SSD Asus ROG Strix Z69-A Gaming Wifi D4