To My Dear @cryptoctopus:

Use AI.

Seriously though, what a great thought you have to improve the use of tags.

Photography is such a wide-ranging term. I might say it is too general to be of help as a tag, so it makes a good example of the problem.

And there are some good ideas put forth here already, and hopefully more good ideas to come.

I suggest you apply some semantic meaning to your tags. This approach might use a "Meta" level tag that is more broad (like "Art" or "News") and you might even describe these relationships using javascript dot notation as has been suggested.

My suggestion is to continue to allow users to create the tag relationships that make sense to them, just like they do now on Twitter, IG, Facebook etc.. but just to focus on dramatic improvement to the user experience.

Data already can be sliced and diced by processors in more ways than v1.0 humans can even understand that data.

Relationships can be explored in individualized ways, improving efficiency to find the info you seek. So the real improvement I am suggesting is in the User Experience. The form of the UI would naturally follow the function.