Problem is that replacing those icons is not possible as developers usually don’t expose a customizable icon, see System Tray Icon Identifier Tool?
Panel Colorizer only recolor the icons, not perfect but better than nothing.
Actual icon replacement will be possible in a future version, see [Feature Request]: Replace icons in system tray · Issue #198 · luisbocanegra/plasma-panel-colorizer · GitHub
The best way to do this was GitHub - bilelmoussaoui/Hardcode-Tray: Fixes Hardcoded tray icons in Linux but is unmaintained.
The proper way to fix this is by applications allowing the icon to be replaced with a named icon from the theme, then one can just switch to a different icon theme or provide the specific icon, an example of such program is Steam. An example of a program that forces its own icon without named icon support is Discord.