Need clarification regarding turning scenes into addressable.

My game will have downloadable levels at some point. That's why I tried to use the addressable system.
Now, every level is an addressable packed separately(with dependencies managed). But this is very annoying to manage. I would like to put all levels(scenes) into a single group.

But the docs seem to say that addressables in same bundle cannot be unloaded separately. I keep scene asset references and call loadsceneasync(mode.single) on them to change levels. Assuming the thing about bundles applies to addressable groups wouldn't that mean that changing levels would keep old level data in memory if they are in the same group?

And I'm also unsure about how the addressable system even unloads the old scene by default.
Honestly, I'm confused. My game is simple enough that I'd rather have bool that checks if the player has bought a DLC instead of this mess.

 

I tried putting all of my addressable scenes in one group. Loading a scene caused unity to crash?

 

And I'm getting a tree view error for some reason. Purged the addressables an rebuilt it but it keeps crashing everytime an addressable scene is loaded.

 

I also don't get any drop downs when clicking on an assetreference field in the inspector.