I updated to Android 12 Wednesday (build number FP4.SP1Y.B.041.20230109). Since, I can’t make the internet tethering work. I tried USB and Wi-Fi 2.4GHz, and I have the same behavior : my computer can connect to the phone, get an IP and ping the phone IP, but when I want to access internet I get the “Destination Net Unreachable”.
Disabling the hardware acceleration for internet share in the developer menu doesn’t help.
For me my usual setup of USB tethering mostly works, but there’s a serious problem after updating to Android 12: every so often the tethering just stops, with huge ping times and missed packets as far as I remember, but then returns to normal when I wake the phone.
Which operating system are you using on your notebook? I had some problems with Arch Linux and USB tethering a year ago and it took me quite some while to understand that I hadn’t set up systemd-resolve correctly.