Taskbar icons looking off was one of things that I immediately noticed after updating from 7 to 10 and then to 11. However, after I installed StartAllBack and enabled "large icons" setting, the issue went away and I forgot about it for years. Nowadays, when I look at older screenshots of my 10 or 7, I barely notice the difference.
An observation and a rant. Many will not even notice that icons got more blurry with Windows 10 and then worse, but I needed to get this off my chest, and perhaps I'll find likeminded minds in this regard through this.