Hey JB!
I personally have no experience receiving Syphon in Max/Jitter, only the other way around. I just posted a device that does this in this thread, perhaps you can take a look at that as an example.
It’s been quite a while since I last touched that device though, and this is more of a Max support question, so I recommend asking around on Max Discord channel. Hopefully there is someone there with a bit more experience on this matter 