How to fix 'The available app icons include a default icon' when publishing an electron app to windows store?
You need to change the default icon provided by Electron (which is the logo of Electron). This icon will also be used in the Windows Store, and it would obviously not reflect your app.
You'll find it under this path in your case:
windows-terminal-tweaker/renderer/public/favicon.ico
You probably just forgot to change that file too, as every other icon seems to work :)