Asset Reimport and Reimport with new File - failed

Problem is still prominent.. i even cannot fix Warnings of missing assets when packaging.. even the assets exist.. unreal simply cannot find the source files, which are located directly in the same folder as the uasset..

To recap stuff:

The problem is pretty much:
Importing new Assets do works.. - F.e. importing a new PNG graphic.
Rightclicking the Asset (even the previous new imported ones) in Content Browser and choosing any Reimport option – Fails..
Opening the PNG with any graphic Program and changing a color.. saving.. Unreal recognizes the update – fails to update/reimport..

I also tried to open specific assets and checked – also changed – the source path..  also does not fix it..

I literally have to delete the whole source file – which also deletes the linked uasset.. breaking all references..  to import a new updated asset..

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And for the packaged game..
it packages without any problems.. no errors..  some warnings about skipped files cause it couldn't find the source (it literally is in the content folder, beside the uasset)..  but the cooking packaging Exits successfully..
When i open the packaged path..
Windows/Projectname/Binaries/Win64/Projectname.exe

And try to start it..  no matter if with a doubleclick or CMD (with  -log Extension)...
It just does nothing.. so no log gets created.. no events fired or created...
Same happens after uploading to steam.. it just is not starting up..