I can’t help with the Dev code.
But I can help with Android and how to install stuff you can’t get in Play Store.
Go to an APK mirror site and search for the app you want. There are usually different versions, some work some won’t work, related to Android versions and the DPI and orientation.
Download on a device which can save to Flash drive. Drive must be FAT formatted which is usually the older smaller ones. Don’t need much storage anyway.
Insert to the Capsule Max, find the file manager if it doesn’t pop open automatically, then find your drive and the file and open, that will install it. If doesn’t work try different versions til you’ve exhausted all the versions.
I had the Max for a few hours a year ago and I did this just fine, it was easy, I didn’t take screenshots so you’ll have to be a geek to nose around, nothing was difficult.