Too many questions lol.
In general you can access secret sub content on the dom route by choosing submisive choices to Alessandra (& also your secretary (& possibily the Doctor) in ch 7, but the content isn't there yet)
On the sub route, if you play competently to rise up the ranks, you can get to k4 & above with subk5, subk6 ranks. (This also gives access to the Alessandra secretsub ruote from the sub path)
These should suit your requirements.
An old reply of mine should be helpful to you:
https://f95zone.to/threads/karlssons-gambit-v0-7b-final-grym-gudinna-games.50840/post-11027824
Especially the last part where the ranks are explained, specifically:
K4 → only way for a sub to move up without being a secret sub down the road. (can lead to higher ranked normal subs) Special note: It will be almost impossible for a true sub Kane to reach Z rank UNLESS an incredibly powerful Olivia someday opts for this kind of change. (basically, the Board as currently constituted will never go for it)
subK5 → A sub Kane can be "promoted" to K5 to close out Episode 8. For gentle femdom lovers (highly competent Kane serving more akin to a butler/servant/admin assistant type role/even limited management duties long-term if trusted) this is likely the best long-term path to take.
