Packing windows generated project on mac

Hello everyone

I am currently working on an archViz project which should be playable on windows and mac. The project was created in version 4.20.2. and done with blueprint. On windows everything works perfectly also after packing.
When I open the project on my mac machine, everything works perfectly too (except for a few little things I have to change in the blueprints). I have multiple streaming levels and light scenarios that get loaded using blueprints (one of them at begin play). Now when I package the game everything goes through succesfully. That’s when the problems start:
The packaged games always have different sizes (sometimes 200mb, sometimes 1,3gb), when I open the game it seems like the streaming levels/lighting scenarios are missing, sometimes it crashes at startup. I only get my persistent level. I have been reading alot of forum entries but I haven’t found anything so far.
I don’t know which part I’m missing. According to what I read the transition to mac should work flawlesly?

Is there anything I need to consider/change in the project to make the package work correctly on mac? I have also tried packing a template generated on my mac and it works.

I’ve the feeling I’m missing an essential step in converting to mac, but couldn’t find any answers so far. So any help that could lead me in the right direction would be highly appreciated!