You are correct, that’s not a proper solution, if you have many unused maps in your content folder you have to add all of them to the blacklist below that settings, otherwise the package size will be huge and the build time could increase a lot.
The approach suggested by @JaredTherriault is correct, it’s better to whitelist all the maps you need to be sure that all the levels you need are selected (in 4.27 AFAIK Unreal used to build all the levels by default if that list was empty, I don’t know if something has changed)
My doubt is: are you writing the level path correctly in the whitelist?
It has to be something relative like “/Game/Folder/LevelName”
I’m currently using “load level by name” in an Android VR build with this setup and it’s working just fine