The Last Sovereign is a pretty good game, it has a lot of content, it manages to not fall into the worst tropes you could have with such a game and it delivers a lot of content, while not having the same problems that other long games have and being stretched super thin in terms of sex scenes. There are plenty.
The gameplay itself is standard RPGM stuff, if you can't stand it, its not for you, if you can, it's pretty good, its not just "number go up", but does use the system it has, making use of different compositions, tactics, etc.
Ironically, I think the sex scenes are the weakest part about the game itself. The describing text is more varied and detailed, the illustrations are serviceable, the amount if pretty good, but I feel like they leave a lot on the table in terms of variety of encounters. It gives you the power to basically seduce everyone, have an MC that doesn't want to do that, but women throw themselves at him regardless. They have to repeat constantly how addicted they are to him and even the succubi have to repeat how they can only have eyes for him alone over and over again. It kinda feels cringe in a "deeply insecure" way in which it must be made perfectly clear that the hero can have anyone they want, but everyone they want will only ever have eyes for them. (Except if its a lesbian encounter, of course) You have some content that crosses that line, but on the whole, it feels pretty tame in that regard. You end up with multiple succubi in your party which all largely refuses to be any different than any of the other characters in your harem. Leaving a lot on the table.
In terms of variety, I'd say that there are also some deficits. A world with endless possibilities end you end up with countless women that have a similar body type, interchangeable scenes and little variety.
But that doesn't mean I didn't like the game, far from it. If you're in the mood for a long RPGM game that isn't sparse with its sex content, this one is a very good bet.