I reported bug 1907764, deemed a duplicate of this. I've installed the latest proposed Ubuntu kernel, 5.4.0-61-generic, under AMD64 and the system is stable with my TP-Link AC-600 adapter installed. It even works!
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1906770 Title: Kernel 5.4.0-56 Wi-Fi does not connect To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1906770/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs