I can’t speak for iOS but for Android the official app allows you to download the files but you have to watch them in another app. There’s a 3rd party app for Jellyfin that lets you download and watch in-app. It’s peak open source fragmentation.

Server transcoding is there and works great though.

Great game but you need to go in with the expectation of a Devil May Cry-like and not a traditional Final Fantasy. If that doesn’t sound like fun, this should probably be a skip.