is there a difference
No.
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tl;dr
Well, for one thing, all games are for gratification, else they would not be games. Also there is absolutely no situation or framework where it is necessary to show explicit nudity to tell a story, especially in a game where you control every pixel. So if you put it there, you did so for a reason. What audience do you expect by doing so? Minors? People that only enjoy looking at naked pixels in an artistic non sexual way?
But to answer your question:
Itch has no age recommendation or rating. It is yes or no. There is no inbetween.
The users see "[ ] Show content marked as adult in search & browse"
The publishers see "[ ] Has sensitive content — This project is not suited for minors or the workplace"
Intent does not matter. If you show explicit nudity, this is considered not suited for minors or the workplace.
You can think about it another way. Would a walkthrough video of your game be allowed unrestriced on youtube?
So maybe consider removing the explicit things. There is hand bras. Underwear. Different angles. Strategically placed environment. You control what the player sees. If they see nudity, it is because you chose so. Even censor bars for comical effect are an option, if you have a 4th wall breaking funny game.
The part about not suited for minors can also involve non explicit things. A pure text adventure about sex would fall into this.
For tagging, the nsfw marking is meta information and those games only appear to users that have that option activated.
Actual tags are not relevant here. But you will get a reminder to mark it nsfw if you select tags like "adult". And people browsing for "adult" will expect explicit games. A lot of violent, scary or bloody games are in the nsfw category. Or other games that are just not suitable for minors in the eyes of the developer.
An age recommendation sure would be nice. But indie games typically are not officially rated and the age recommendation would be different for different regions. Very different.
So your game might be T or 12+, but still nsfw on Itch ;-)