Yeah this was tagged as game ready but well I tried it with SceneKit and it was even bigger disaster :-))) all the model was just black. Unity somehow managed to live with this but still not perfect - some shadows were completely off.
I tried several blender tutorials it didnt help- now I am going to try to make Auto UV channel will update tomorrow if ot helped.
Bit honestly I encountered another model SM_PineTree from landscape package on MarketPlace (I think by Epic) and it had 87.6% overlapping UV when I migrated it to my project - however in landscape project I have no warnings about UVs and lighting.
I think I am missing something here.