No need to be sry. DH uses some unique addons for the models, mostly about the interaction between models. For those reasons, just having the game code would not be enough. You need to have everything. But you can make gay stuff without problem but DH did not make the game with all the possibilities so you can't just chance some parameters and got the gay sex. I am not so expert about those stuff but rather then modding it would be better to re-code it.
Botn is not a masterpiece. Concept is copied from Breeding Season and turn into a 3D world, which can be done even with assets in unreal and some simple mechanics. DH saw the opportunity and did the right thing right time. He is a game dev as a job so he is not someone random who wanna learn how to make games. If there is a free UE5 developer out there, who can code the simple roaming/zoning mechanic can find a modeler/rigger and an animator and viola. I am a designer and animator so, 2 people and some stuff out sourced can easily create an awesome breeding game.
I still think Breeding Season is better. It's clearly designed by people who knows this stuff, good art choice, very brave and open content but they fly too high and burned in the sun. I think breeding games should be fast. Nobody cares the mediocre animations after few times and you just spam breed until you get better and better results. Yes, visuals are important to get people but the game part always more important. Like the Palworld against Pokemon.