I'm Not Even an Otome Game Mob Character
Otome Game no Mobu desura naindaga
Publisher: To Books
Genre: Slice of Life, Isekei/Tensei, Fantasy
Volumes: 2 (Complete)
Synopsis: MC is reborn with memories of his past life and lives as an apprentice gardener in the duke's estate. Eventually realizes he's in the world of an otome game he helped his sister play in his past life. Doesn't particularly care that it's an otome game world though as all the game's routes won't result in a problematic life for him or his employer.
There is a manga for this by the same name published through Square-Enix, but it's (officially?) coming out in English through the MangaUp platform now.
This novel appears to be complete at 2 volumes, though the author seems to have written some side stories on syosetu which don't appear to have been published. This is more sort of a sweet slice of life type story since the fact it's an otome game world only loosely plays into things as far as I can tell. There's a lot of antics as he ends up interacting with people way beyond his station in life.