Sure. I guess I am speaking about the larger trends. Firefox just recently went full rounded corners on the tab 'buttons'. Google did the same 2-3 years ago. Purple-gradients has been the trend that began with Stripe and spread around in design circles, landed at Apple sometime in 2018.
With what product, specifically, did purple gradients land at Apple? Looking at the screenshots of Monterey it seems to me that the purple you see is probably from the desktop background, which is visible through the translucent UI elements. There are purple gradient elements on the web page itself, but I don't think that's particularly relevant to the actual software.