This series is absolute trash, but it's enjoyable trash.
So many stories with hooks about having 'as much sex as possible' tend to completely renege that hook and not actually deliver on what it claimed, unlike this series which delivers fan service very very often. The actual story may be total wish-fulfillment slop, but story isn't the point of this series anyway.
If I have one complaint it's with the isekai'd heroines - it'd have been better just not to include them at all. It's nice that they don't bring down the vibe by making everyone 'happy', but it's a coat of paint over a very bleak aspect of the story otherwise.
They could have made it so that all the men in the isekai world died out, so they only isekai'd men - there, I just fixed the mass rape issue, problem solved.