Yes...I have myself installed pgAmdin more than 50 times so far. But this, for the first time ever I have faced this issue. Just try deleting the pgAdmin.bak file for the pg15.8 on a Windows server 2016. Try doing that, lets see.
I know its hard to believe this. But you can try doing this from your side and respond here back again.
I can't speak for Robert, but I've installed and run pgAdmin literally hundreds of times on Windows, Mac, and Linux, and have never seen it even crash a whole machine, let alone render one unbootable. We also probably have hundreds of thousands of users on Windows (based on the number of downloads we get), and have never had such a problem reported.