To be honest this looks like an oversight on ItchIO’s part because it’s set so that accounts that uploaded any NSFW content at all will be unable to disable the NSFW content view themselves, even if those accounts remove all of the NSFW games that they posted.
I don’t think your problem will be fixed soon because either an admin has to come to manually reset your account status to no NSFW posted, or they have to alter ItchIO inner workings so that accounts that previously uploaded NSFW but no longer has NSFW content will be re-allowed to adjust their NSFW viewing option.
You should just make a different account for viewing SFW stuff on ItchIO.