Hello everyone!
I ran into this problem and tried absolutely everything mentioned in the forums, including the Microsoft Store where the installation also failed.
My solution was to find another computer where I had a 2021 Epic Launcher (version 13… something, if I remember correctly), and run that installer. It finally worked!
In other words, you need to use an older launcher to avoid the issues with the current one.
Ideally, Epic would fix this, but it was the only workaround I found.
I hope it helps someone!