Third party app icons (Discord, Steam, etc.) are not showing up in the tray portion of the top panel on Elementary OS 6 (Odin). Native icons like network, microphone, etc. work, just not third party indicators.
I believe an alternative was to use Lafydev's wingpanel-indicator-ayatana or wingpanel-indicator-namarupa but none of them are working. I added this to the indicator-application.desktop file:
OnlyShowIn=Unity;GNOME;Pantheon;
Manually started the indicator-application service, this was the output:
/usr/lib/x86_64-linux-gnu/indicator-application/indicator-application-service
(process:4600): indicator-application-service-WARNING **: 19:54:31.377: Unable to get >watcher name 'org.kde.StatusNotifierWatcher'
(process:4600): indicator-application-service-WARNING **: 19:54:31.377: Name Lost
Those wingpanel apps were supposed to fix this but for some reason they just aren't working.