Mac OS App Icon Color is same and is confusing

Part of what you see could be due to the "Liguid Glass" option in Tahoe. Its translucent backgrounds as in the Dock can make icons harder to see. Things to try:

Do System Settings .

— In Appearance:

• set Liquid Glass to "Tinted

• In Icon & Widget Style, try "Dark" to change the icon background:

— in Accessibility > Displays, play with the options at the top of the window\, focusing on these three:

And, as Apple will not see comments about their new user interface in these user-to-user forums, I invite you to use this feedback link to give Apple the scale of user reactions to their new look:

Feedback - macOS - Apple

Seems like a case of guilt by association.

There are 64 Apple apps in /System/Applications. Only about 8 of them (13%) have an obvious blue colour. I'm including "Bluetooth File Exchange.app" which should obviously get a pass.

Most of the apps you have listed are 3rd party apps. Of the built-in Apple apps you've shown, half aren't blue.

It's true that Xcode and its helper apps are blue by default. Finder is a special case, and blue.

But if you don't like those default colours, macOS 26 now has a feature in System Settings > Appearance > Icon, widget & folder colour that will turn all icons whatever colour you prefer.

See >System Settings>Appearance some changes got turned on during the upgrade...

this seems to work better for me:

I also do not need suggested/recent apps in my Dock taking up sapce....

you can submit your Apple Feedback here: Product Feedback - Apple

I don’t have it enabled, but it is my best guess as to what you are seeing, turn of icon tinting.

I have mine set to dark mode with no tint and don’t have any problem with discerning which icon is which.