Hello there @voltsm! Let’s see what we can do here.
Since your current project was on a previous version of Unreal, and its now updated to 5.1.1, all previous settings from the old build are most likely causing a conflict.
To clear you engine settings, delete yourproject/Config/DefaultEngine.ini. Then start an empty, new UE, and open your updated project. This should either recover your project, or crash again but return an error log.
Using said error log should allow us to pìnpoint the problem. For further details, please check this related thread: