Unfortunately with SSH specifically, the dissectors aren't very mature - you only get valid parsing up to the KeX completion messages (NEWKEYS), and after that, even if the encryption is set to `none` via custom patches, the rest of the message flow is not parsed.

Seems because dumping the session keys is not at all a common thing. It's just a matter of effort though - if someone put in the time to improve the SSH story for dissectors, most of the groundwork is there.