This is partly because even today, it feels like 90% of all games have male MCs. People are simply fed up with it; the market is oversaturated. They're looking for alternatives. There are more and more games with good female MC
Aside from that, Multi Mc and Female MC is a good trick for making NTR content socially acceptable. People had never have a problem being predators themselves, banging everything they can, even if it means tearing a LI out of a healthy relationship, although that's also a form of NTR. But not a few people riot when a LI does the same thing without their having any influence over it. However, if you slip into her role, as another female MC, and make the decisions, this anti-attitude suddenly changes. How many people are here who make Lena being with Ian and play her absolutely loyally? I think that's the minority. Suddenly people were looking for her cheating, although it makes no difference in content.
And more and more developers are discovering this simple trick for themselves, It is currently one of the best ways to "hide" NTR. And it actually works great.