To change the app icon in notifications on OneUi 7, you can toggle the “Show app icon in notifications” setting in Advanced Settings. This setting is usually found under Notifications in the system settings. If enabled, the app icon will be displayed in the notification drawer. If disabled, a custom notification icon set in the app will be shown instead.

Here’s how to do it:

• Open your device’s Settings app.
• Tap on Notifications.
• Select Advanced Settings.
• Turn off the “Show app icon in notifications” setting.
• For more details go through below image