You can't ping people on Itch. This is not a social media platform to contact and chat with users. You cannot even contact users directly. Nor developers.
A black line between two genres means that, from the perspective of my current system, those genres are essentially the same.
If that is so, your current system's perspective is very wrong. Breakout and platformers are nothing alike. Hidden objects have nothing to do with visual novels. There is many more such examples.
The issue is, if you try to analyze tags on Itch, your system's data is bound to be faulty. Itch tags are not accurate and you do not know the ranking of relevance, even if they would be accurate.
I am still unsure what you are trying to create. Is your system trying to tell people that like breakout, that they will like platformer games? Or if they like visual novels, that they will like hidden object games? Because, that would fail. Exhibit A is me. I do like some platformers, but I never liked breakout. I like some visual novels, but I do not like hidden object games.
You might want to double check popular games on Itch with their respective tags on Steam. Steam tags are ranked by relevancy and relevancy is chosen by users.
Let's try this.
Backpack Hero, Tags on Itch
Role Playing, Card Game, Strategy
2D, Cute, Deck Building, Dungeon Crawler, Pixel Art, Roguelike, Roguelite, Turn-based
And on Steam. "Popular user-defined tags for this product"
Replay Value, Inventory Management ,Turn-Based, Roguelike Deckbuilder, Deckbuilding, 2D, Fantasy, Roguelike, Strategy, Building,
Choices Matter, Turn-Based Strategy, Roguelite, Casual, Procedural Generation, Singleplayer, Card Battler, Controller, Female Protagonist, Moddable
The developer chose role playing as a genre. Users disagree. It is not even in the list of the 20 most popular tags. Neither is card game, though deckbuilding is used. Nor Pixel Art. Nor Dungeon Crawler. And Steam has a cute tag. But users disagree there too. And yes, the characters are cute, but this is just not relevant, neither is the fact that it is a pixel art game. Curious, isn't it. Also, the game centers around inventory management, but on Itch no tag indicates such.