How we can change the nav bar symbol (icon) with app metatdata

Hi@all

I will make different icons for the the nav bar app an select this (Symbol-ID) per Parameters (metadata) in the APP Config

i have set settings in icon_nav_bar.svg

<svg xmlns="http://www.w3.org/2000/svg">  <symbol id="default" viewBox="0 0 990 990" ...>    ...  </symbol>  <symbol id="count-1" viewBox="0 0 990 990" ...>    ...  </symbol>  ...</svg>

When i open zendesk, the app ist view in nav bar with default Symbol
The app.registered Funktion ist not fired

This Workaround : Dynamically changing app icons | Zendesk Developer Docs is not working for nav bar

How we can change the nav bar symbol (icon) with app metatdata by start the APP (start Zendesk) - not clicking the app

Sorry for my english, i hope you can understand me.
Thx@all