After having a friend fail to launch the game after a reboot, I had decided to test it myself.
I rebooted my machine and from a cold boot, started PSO2. UAC prompt appeared and it got to the launcher. When hitting Play, nProtect reported a problem and closed. After that, the launcher would no longer appear.
Rebooted again, same problem where the launcher won't load and no UAC prompt appears. Uninstalling the game is failing. Launching via Microsoft Store is failing. "Repairing" via Win10 is failing. "Reset"ing via Win10 is failing. (The throbbers just run in circles but nothing is actually done.)
At this stage, the client is unusable.