Which 100 Gbit/s transceiver do you need for this?

This will not work. The converter can do Ethernet, but the SFP+ module is XGS-PON and still needs an ONT (e.g. for encryption (AES128) -> the hardware needs software). A Zyxel AX7501 works with the right settings (is officially certified by Swisscom).

Where did you get this STP+ module from Hisense? I am looking to purchase one, but no luck. Thanks in advance.

I would be interested in that too.