Yeah this really ruined the game for me too need to make a whole new character now. So just on here looking for a gallery unlock save and then going to remove this game. The content is just too repetitive and the game is not finished a lot of parts say "this feature will be added in the future" yet apparently the dev has stopped working on this game so lol....? Also had quite a few bugs as well so.
That is because you are playing the game wrong, but that is not your fault, the game is badly designed despite looking good on paper at the time, so sorry for that.
I am not sure if the manual ever mentions it, but the
protagonist is the protagonist of the story, the one where you can play the game from start to end and get the true ending of the city (Kartedhir).
You cannot play past the ending (obviously) but the save does not get deleted.
What gets deleted are the saves of the secondary characters (Females), if you were to make a slave then purchase her with your protagonist character, her save will get "absorbed" by the protagonist's. Not quite deleted, but you will not be able to play from her perspective anymore.
That is the only time that happens as far as I can remember... Your secondary character can get the toilet profession and brothel profession and continue with her perspective even if the protagonist interacts with her.
The game should not display that message anymore, it is most likely a bug calling the wrong dialogue or somehow it is trying to access one of the cut features.
The game has all of its features completed, and so is the story (three endings).
Last but not least, the gallery is persistent, so it does not really matter how many playthroughs you do. You can complete it even if you start 10 characters, at the very least it cannot be completed with a single playthrough or by playing only protagonist/secondary characters.
The game is fairly short for each route, and very few things require previous checks, so repetition should not be an issue.
The only repetitive thing I can remember of is the Ouija Board quests, but you can fully play that questline once or until you get the BDSM access thingie... Even that does not unlock any gallery cgs as far as I can remember, so it is an optional extra.