Paul Kafasis on the Rogue Amoeba Blog: Free The Icons:

With last year’s release of MacOS 26 (Tahoe), Apple made a mess of app icons. In the first betas of MacOS 27 (Golden Gate), however, there are signs of a turnaround. We’re urging Apple to continue making improvements, by restoring the ability for MacOS app icons to have distinct shapes.

I wholeheartedly agree. I get why Apple did it, but I think it's completely wrong for the Mac.