The game is fine.
If you play AVNs for the N bit, there's tons out there which do not have the A bit, and are just dedicated Visual Novel style games, which are a millions times better than ANY AVN because they are made by major studios.
If you play for the A bit, this should be SSS Tier for you, as the scenes are great... not as long or immersive as some... but beautifully done.
If you are playing an AVN that has this 'weird' trope you mentioned, expect them to be a little batty, because they HAVE to be....it is taboo sexual fantasy, that is very rare irl, and most people cannot imagine a logical, realistic, scenario in which it could happen... ...because most of us do not do that kind of thing, never have, so have no metric to judge such, and those who HAVE, are stigmatized in almost ALL societies... so I doubt they are making AVNs, and if they DO, they likely will not be using the real world experience of how they came to be sleeping with half their family as the narrative.
If you play AVNs expecting both amazing A bit, and amazing N bits... then what can you do, they do not exist, even the very very best in the genre do not blend both flawlessly.... they cannot.
Most 'Artistes' with a story living as a song in their heart they just have to get out.... choose the AVN format, over just a plain old VN one, to simply broaden their reach.. You almost ALWAYS find the adult content is cheap, quick, BS, limited in quantity, duration, and quality, and usually not even necessary for the story (as in retrospective confirmation, implication and suggestion, symbolism, or good old Fade To Black would work just as well and make NO difference to the game) but just there as a gimmick and to let Adult and NSFW tags do their thing, and draw in players from a smaller competition than going up against aforementioned VNs made by big pro studios.
Most AVNs where the ADULT bit is CRITICAL and even foundational to the story, have major issues with narrative... because at the very least, even leaving out crazy rationalisations, contortions in morals and logic, tenuous associations and interpretations etc etc to justify the extreme fetishist, or very taboo things.... the narrative still needs be one which somehow explains the F ton of sex going on. That is almost impossible to do realistically, when by the end of an in game week the MC is meant to have banged his neighbour five times, his classmate thrice, once with his Uni lecturer who they've also banged separately half a dozen times, his sisters best friend... and his sister.... and mom.... and.... grammie at least four times. The result being rather simplistic, unrealistic, at times repetitive, at others just batshit cray cray narratives, that are basically necessary to move the carnal narrative, which is the games core, along.
Even the very very best games on here... the highest rated, like Eternum, or Ripples or Pale Carnations, go all in on the loopy edgy crazy unrealistic BS at times, because they could not be the games they are without it, and still hit all the adult content beats they do.
And who says choices have to matter? Sure agency is great...but there are FAR FAR worse games for removing all agency from the player. Play Harem Hotel deep in the late game, or what there is so far in it... and it a pretty long game even unfinished... and then enjoy being a spectator in all your girls dismal failures to do what needs doing to address the social injustice which becomes the overriding narrative of the game instead of the Hotel or the Harem. Talk about choices not mattering and lack of agency, sheesh.
Also... Annie's Anal Surrender is all the reward system anyone should need, and if that is less important to you than immersive narrative, I suggest you stop playing games, and go read some the classics of idk, 19thC Russian literature. This is an AVN. Not Tolstoy, sorry.