Used zypper dup to upgrade to Tumbleweed 20210311 (kernel 5.11.4-1), after reboot, screen shows Tumbleweed logo, BUT boots to CLI login. Neither X nor KDE starts. Cursory exam of /var/log/zypper.log didn't show any problems (but given volume of data may have missed something), but checking Xorg.log shows (at 1297.567) "Failed to initialize GLX extension (compatible NVIDIA X driver not found)". System worked fine with 5.10.x series of kernels, but no GUI with 5.11 series of kernels. Zypper erased kernel default -5.10.16-1.2.x86_64, so can't fall back to older kernel. Suspect that NVIDIA drivers were not retrieved/loaded, but not sure how to rectify problem

Checked /var/log/messages and for 2021-03-03 PackageKit was successful and "plasma-pk-updates" finished successfully. Starting 2021-03-08 showed "PK error" packman "repo-not-available" and "plasma-pk-updates" failed