the most difficult thing is to understand on which route you are lol. Futa on futa is obvious, the one I don't understand si the diffecrence between netori and depravation route (sure you have that variation scene with purple head but apart form that?)...
Basically it goes like this:
1. Netori
2. Depravity
2.1. futa x futa (being a sub-route to depravity
2.1.1 futa x futa (semi-dom)
2.1.2 futa x futa (sub)
Difference between netori and depravity in general would be:
In Netori Route Milly (the MC) makes an conscious decision about wooing others getting laid (cucking others/stealing other's LI -> netori). Or in simple terms: Milly recognizes her desires and she's clever about 'romancing' other characters and thus satisfying her urges instead of becoming a victim to those.
Depravity as it was in the initial version was practically refraining from acting on getting others LI at the expense of her willpower (Milly would at some point be overwhelmed by her desires and would pounce on Hana -> also the reason for the rape tag)
As previously discussed/mention by others: futa x futa route opens up in the depravity route and can only differentiate in details as to Milly be full sub or trying to grasp at some semblence of dominance over certain partners