Let me demonstrate it with WeChat version 8.0.33:
1. Open WeChat and click Address Book.
2. Click on the official WeChat account.
3. Click the "subscription number" that needs to be cancelled.
4. Click "Avatar" in the upper right corner.
5. Click to follow the official account of WeChat.
6. Click No longer to pay attention to it.
Disclaimer: This answer is original based on my real experience, and I refuse to reprint it without permission.