to uninstall Aurora just delete the folder its in
If you are going to go to the extra effort of looking for a way to bypass the 2k launcher might as well just use the old method and run it via steam tinker launch, it seems to work with STL.
The problem it's having is that it is detecting that it is being launched by Aurora Launch Tool and not through Steam. I've encountered this issue when I first started finding out ways to run Epic/Ubisoft games that were "found" by Aurora. I spent countless hours figuring out ways to get Epic/Ubi games to work and I would recommend just skipping the bypass and run it through Steam Tinker Launch.
Save yourself the headaches.
I've found and fixed the issue with Marvel midnight suns and our SD tool. The root of this cause is more generic so it might also fix the launch of other games which have failed before. An update will be released in the next few days.