I reverted the VM, installed the SSU, installed the Office updates, then ran the FlashUninstall update.exe, it sat at Initializing installation for 30 minutes with a TiWorker process using 100% of 1 CPU core for most of that time. Then it reported the update was installed successfully. I shut it down and snapshotted it, then started it back up and ran the 2021-01 Update KB4589210, it completed successfully in a few seconds and wanted a reboot, after the reboot I tried installing the 2020-02 CU KB5010359 and after a while it had the TiWorker crash.