No reinstallation needed.
After you have upgraded your system to Tumbleweed, but before you reboot, you need to bring your graphic drivers back into order.
Two steps are needed in the process.
In the upgrading process to Tumbleweed, ALL packages get switched back to openSUSE including some driver packages. That is expected. But you need to switch the graphics drivers back to Nvidia repo or you will have a version mix (nvidia-modprobe is the critical package).
sudo zypper dup --from NVIDIA --allow-vendor-change
P:S: for the above command the Nvidia repo needs to be present. No clue why it is missing in your last output.