Using Chromium Edge 88.0.705.74
Using builtin feature "Install this site as an App". Have been using this feature in Chrome and Chromium edge for a while. For sites that do not have a Favicon.ico, a black icon is substituted for the app.
Prior to msedge version 88, you could create the shortcut for the app on the desktop, modify the icon within the shortcut and then pin that shortcut to the task bar. Then the icon on the taskbar would operate as an app. This procedure still works within Chrome 88.
I am not a developer, I am a Systems Administrator managing many systems that now have web based admin consoles such as: vSphere, Windows Admin Center, Azure, Microsoft 365 admin centers etc.
As an administrator I don't know a json from a manifest, I just need to open a web admin console, create the page as an app, select a relevant icon and pin it to the taskbar.
This functionality has changed in Version 88 of MSedge.
In version 87 of MS Edge it would pin the app to the taskbar with the Icon.
Still works in Chrome 88
For more background, here is the thread on MS Q&A ms-edge Chromium Edge - Install this Site as an App - Modify Icon