Is it possible to change native app icons in Big Sur?

Hi

To me it is the opposite, I installed Big Sur on my MacBook Pro, it works perfectly, but the App-Icons didn't changed like on my iMac Pro (they stayed Catalina App-Icons).

I'll now have on my iMac Pro and my MacBook Pro, the same MacOS, but with different App-Icons!

ps. all the Apps have the same update (latest) versions

Is there a solution for?

that's my dream setup...I'm already considering buying a MacBook Pro 16 inch now just cause I find the look of the new icons hideous. but I'd also want Big Sur for..well for the future, really for no other reason considering I hate everything about the looks.

No, the icons of the apps are permanent, they change in every update, but you can change your software update to a previous one (only if you like it and find it convenient)