I have same problem on sendto with ipv4. The code works well with iOS 18.0 simulator on Sequoia, however, sendto returns -1 on macOS Sequoia. Privacy - Local Network Usage Description is set in Info for both iOS and macOS. This privacy setting doesn't affect to this problem.

I have same problem on my M1 iMac. There was no such upgrade problem on my Intel iMac. I tried the upgrade from Beta 4 to Beta 5 many times. But I have never succeeded the upgrade on my M1 iMac.

I had a similar problem with Monterey beta 3. When I update from beta 2 to 3, it began to fail booting up. Then, I tried to make clean install in other SSD. Beta 3 could run successfully. I checked kernel extensions. I found one (installed from SATSMARTDriver-0.10.pkg) of USB device drivers killed Monterey beta 3. I couldn't update from Monterey beta 2, and/or Big Sur to Monterey beta 3 because of this USB device driver (kernel extension). I hope next beta version will fix this kernel extension problem, and I can update my current macOS version without clean installing.