Tried to search on the internet and even asked via ChatGPT Pro. I’m struggling to delete these categories as indicated by the screenshots, hence posting here for help.
AI-generated summary
The discussion revolves around deleting default categories with chats in Discourse. @stanigator is struggling to delete the #staff category, which HamMan2118 and Heliosurge point out is a default category that cannot be deleted on its own. Instead, Heliosurge explains that the #staff category is a special category for moderators and admins, and Lilly suggests checking category permissions. Lilly also provides a link to a topic on understanding groups and category permissions, and later shares the chat documentation to help with chat settings. Heliosurge advises using a category with public permissions for a public chat channel. Although @stanigator is still struggling with chat settings, as seen in post6, deleting chats in the staff category may not be as important to address now, as mentioned in post9.
Do you have a chat channel for the #staff category? Make sure you check both the Open and Closed chats in your forum.
If I remember correctly, on its own, the #staff category cannot be deleted as it is a default category when you create a Discourse forum.
Correct the Staff Category is a special Category. It is also where you will find the “Terms of Service”, “FAQ”. And you can also use it to upload other assets.
But is there a way to hide them or not make them visible to the public?
Hi @stanigator 
welcome to Discourse Meta 
So what does this tab say about the category permissions?
I can see from your sreenshot that it is secured because it has the lock icon.
This topic may help:
The Staff Category is intended for full moderators & Admin only .
If you’re looking for a public chat channel you can use a category that has permissions like
Everyone; See/create/reply
which settings specifically?
chat documentation is here:
Deleting chats in staff category. But may not be as important to address now.