I just made a minimal project from scratch using the embedded version of the UnrealEnginePython plugin. I installed pyside2 and it works. I’ve created a repo on bitbucket Bitbucket. perhaps you may find it useful. I excluded the plugin folder from the repo because my version of the engine is 4.19. But if you used the embedded version of the plugin for your version of the engine, I believe it should work fine. All the features I was using in the source version have since made it to the release packages, so there is no longer a need to build from source.