I did see your stream last night on ZS but it was very choppy.
Try this. Go to zap.stream
* delete side data and cookies from your browser
* re-auth with the site after it refreshes
* go to dashboard -> providers and select one
* to to dashboard -> settings and grabs stream URL and key
* top up with SELECTED provider.
As for re-streaming through Streamyard. Have you tested if the problem on nostr persists when streaming directly (with OBS)?