I’m not familiar with conditional trigs. Could you feed a MIDI track back to the DT (externally) to change patterns with a conditional trig, so pattern A repeats 4 times then triggers pattern B that repeats twice, etc.? Essentially build the song within the patterns. Not ideal but might be a workaround.
I can’t believe that the pattern chaining is intended to be the “replacement” for song mode. The pattern chaining is an expanded version of what’s on the MD and feels like a basic, expected feature rather than something new and replace-y.