get netflix password from my own fire stick?

edit

but is it possible using wireshark although it is certainly a SSL protected athentication process?

No, it's not possible, as the data between the stick and the Netflix servers is encrypted. As you don't have the private key of the Netflix servers (unless you're the Netflix server admin, or an uber hacker), you can't decrypt that traffic, which is good, otherwise SSL/TLS would be useless.

You can use a proxy on the Fire TV stick to intercept the communication, however if you're doing SSL/TLS man in the middle on that proxy (see link below), you must install the intermediate CA cert of your proxy on the Fire TV stick, and I doubt that the Netflix app will use your cert. However, I've never tested it myself.

https://developer.amazon.com/es/blogs/appstore/post/58201cb3-9b41-4567-a037-65a9d4f979a7/viewing-secure-ssl-https-traffic-from-your-app-on-fire-tvs-running-fire-os-6

But honestly, before you do all that, just use the password reset option. It will be done in seconds. The other stuff will take hours or even days to build and test.

Regards
Kurt