I'm proposing that when you search for a hashtag, Maps recommends other related hashtags for you to see the results of. I have thought of two ways to implement this:
Like some social media, where the hashtags would appear below the search text box and you could see their results by tapping them
So, if someone searches for #cupcake some related hashtags that can be tapped would appear below the search text box, in this case it could be #cupcakes, #muffin, #muffins, etc.
By adding results of related hashtags when the results of the hashtag searched for come to an end.
In this way, when the searcher keeps scrolling down and reaches the end of the results, there could be a text that warned that the following results are from related hashtags, specifying of which related hashtag in each of the related results. So, if someone searches for #cupcake, again, when there are no more posts of #cupcake, it could show results of #cupcakes, and others.
Here are some reasons of why I think it would be great to show related hashtags or related results:
Not everyone thinks of the same hashtag when thinking of the same thing. For example, someone might write on their review #donuts, but someone might search for #donut. Someone might even write #donutlovers.
Even in the same language and dialect, the same things can be called with different names. This happens all around the world, but talking from experience in South America every country and even provinces can have different words for the same thing. Even though we are so close, we might have no idea how something is called in another place, or if they even call it differently.
Tourists usually write the reviews in their language. Even if they do speak the local language and can write the hashtags in that language, there are many who can't or won't. In very touristic areas, there are reviews in a lot of different languages, not being able to see related results of the same word in different languages would mean seeing just a very low percentage of the actual results.
Tourists also would search for the hashtag in their language, if they don't know the local language.
In all of these situations, the searcher won't be able to truly take advantage of the hashtags feature, and the places where reviews that don't show up in the results were made won't be considered.
The searcher can try to brainstorm of other hashtags that mean the same or are similar, or search for a translation, but not many people would think of that, or would want to, especially if they didn't get that many results in the first place.
With the related hashtags:
a tourist searching for #accessible in a country where English isn't one of the official languages would easily be able to see the results of #accessible in the country's language or languages.
someone searching for #cake would be able to look at results of #chocolatecake #cheesecake, and more.
i'm sure you can think of other situations.
It would also be great although probably complicated to also implement this: when someone searches for #vegetarian, they would see related results of #vegan, but when someone searches for #vegan, it shouldn't show the results for #vegetarian. This could also be applied to other dietary restrictions.
I'm sure there are many more ways to solve this problems and/or show the related results, if you have other ideas please write them in the comments!
I have already written two other ideas about hashtags, if you're interested in them feel free to click on the links and check them out: