Okay, sorry if I am piling on with the replies here.
Recently Parasite Black by Damned Studios posted a message on Steam that they had reached 60k downloads, Now their game is a dark fantasy, and has artwork that is more exaggerated than Summer Scent (reminds me a bit of Simon Beesley, with a dose of Frazetta sprinkled in), so they may attract a slightly different audience, perhaps bigger than Summer Scent can hope to pull in. It's also more graphic in its depictions, providing greater fan service appeal. Their target audience is not the same as yours. But it could still be a useful comparison.
Their price is set at $17.95, discounted to $13.99 during their introduction. (cheaper still if you get it in a bundle with other adult dark fantasy games) If 90% of Parasite Black's downloads were actual purchases, and if they cleared $10 per sale after Steam took their cut, the math looks pretty good to me, but I have no idea of the expenses and time they've sunk into the game.
Summer Scent is not a dark fantasy and features a different, less juvenile style of art than Parasite Black. For better or worse, Summer Scent is probably not going to grab as large an audience, simply because your game is more realistic, and because you're not writing to fulfill that kind of adolescent power fantasy(and I do not mean to speak ill of adolescent power fantasy as a genre; I bought Parasite Black, played it and enjoyed it!). You might sell more than Parasite Black, but let's assume that you set your price at the same point that they did, offered the same discounts, bundled it with similar games from other devs (cross promotion seems to have its benefits after all), and that you sold half of what they sold in your first few weeks.
Would you consider that a success? What if you sold a quarter of their sales? A tenth? I think you need to decide, before your Steam debut, where that line is. Hope for the best result, but be mentally prepared for the worst possible outcome, have a threshold that must be crossed in order to justify your continuing to be an adult game dev.
You can do some things to improve your chances. Develop relationships with other devs, especially those that have put their games on Steam already or are about to. See if you can arrange to be a part of some bundles. Get people that have a following to review your game on Itch and offer to do the same for them if you like their work. Oppaiman.com seems to be popular with many devs, though I don't know how much help they truly give, nor how much that help costs.
I'm not a dev, and have no experience in this business, but it seems like some devs who have a great game fail, while others who have less interesting games succeed. There's a LOT of competition out there, but also a lot of cooperation and support between competing devs. Try to take advantage of that if you can, starting with the devs whose work you most enjoy. And take what I have said with a grain of salt; like I said, I have no experience!
Sorry for being so long-winded. I've seen games that I loved wither away because they couldn't find an audience. I really don't want to see that happen here.