Topic Channels are generated automatically by YouTube. However, that automatic process doesn't guarantee a Topic Channel under your artist's own name - that only happens once the artist meets a certain threshold of presence on the platform.
When does YouTube generate a Topic Channel under an artist's name?
YouTube creates a Topic Channel titled "Artist Name - Topic" when that artist has a significant presence on YouTube. If an artist doesn't have one, it's usually because:
There are only a few videos from the artist.
The artist's videos don't have many views.
The artist's videos don't meet YouTube's quality standards.
If you already have a Topic Channel under your artist's name, we recommend setting up an Official Artist Channel instead - it consolidates your subscribers and unlocks more features.
More info at YouTube Help https://support.google.com/youtube/answer/7636475
Related Topics: How do I have an Official Artist Channel (OAC) on YouTube?