Yeah, it's very unclear, but it looks that way tbh. Between your diagram and the one I found, both of those don't have Nostr and AP connected. Yours didn't have AP at all so I assume ditto doesn't have it but soapbox can have it but not with Nostr combined?🤔
Discussion
Like I said, the main thing I know about is using a bridge.
nostr:npub1nhalfkgshdnn3dpgmgqyp2ks2hhl8qydwyvqvpwkntswsfg876gqlrmujl built that stuff, he could probably tell you better than I.