What to come up with 18+ content in search?

Question

MongoDB

Can someone tell me the logic or other thoughts on the topic.
The essence of the problem is that there are erotic materials (photos) on the site, they are in a separate category, tags are written for each photo, and there is a search on the site for those tags.
The user can enter into the search, say "Nature", and there mixed with nature and girls naked in nature.
I can’t remove such pictures from the search, the audience of the site is 25+ and mostly men, the women seem to be deterred by the search)) but the man is not bad at all.
What can be done? Only comes to mind:
1. Put a background on the previews with a warning, and display a button, they say you want to watch such content, click here and watch. This is the simplest thing actually.
2. The following also came to mind. Does the site have its own metrics for user requests and can be viewed requests, collect data on tags where unnecessary content pops up and filter it on the issuance side according to the list of collected tags? This is laborious and in some cases will not be advisable.
What else can you think of?