Then I must confess, I am at a loss. If I let the container create the folders, it will do nothing. If I set permissions on what it created, it will download stuff and put them into the folder... but it won't install the server and it won't work. If I delete everything and make the folders ahead of time and set the permissions, it does the same thing as just fixing permissions after it creates the folders.
It does not appear to matter what permissions I change or who I set the user as for the folders or anything. It just... stops there. Every time.
Does it just not work on 6.10?
Edit: For additional information, the FTB Direwolf 20 1.18 container from you works just fine once I fix the owner of the folder it makes.