To test my theory I changed the retryAfterSeconds to 20 in the JUPNP library AbstractStreamClientConfiguration.java. The tv device is registered 20 seconds after power on.
A forum search shows other bindings have this problem too. e.g. Kodi takes sometimes up to 15 minutes to come online - #3 by djpsycho82 and Too much time before a Sonos thing becomes definitively ONLINE - #22 by morph166955. Someone even mentioned to restart the jupnp bundle with a rule.
@J-N-K Can you give me some tips on how to change this code? Where to create a issue? How to create a suitable pull request? Or someone to discuss a possible solution. I assume the 10 minute retry was set for a good reason.