How to change Finder icon on macOS Catalina?

On previous versions of macOS, it was possible to change the Finder icon in /System/Library/CoreServices/Dock.app/Contents/Resources/.

However, this doesn't seem possible in Catalina anymore? Even with SIP disabled?

Based on this answer: Cannot change login wallpaper in 10.15 Catalina?

1. Reboot Mac, holding ⌘R to boot into Recovery mode
2. Open terminal
3. Disable SIP with csrutil disable
4. Reboot Mac
5. Open a terminal
6. sudo mount -uw /
7. sudo cp ~/your-new-icon.png /System/Library/CoreServices/Dock.app/Contents/Resources/finder.png
8. Repeat for [email protected]
9. Reboot into recovery
10. Re-enable SIP with csrutil enable