oh FUCK no
So they're not basing it off the Silmarillion, but it's set before LOTR, so I take that to mean it takes place some time in between The Hobbit and LOTR takes place? Maybe they'll tackle some stuff from the Appendices, such as the lineages of the kings of Arnor. There's a lot of material they could explore tbh, maybe the rise and fall of Númenor. Although the story of Númenor takes place in Akallabêth in the Silmarillion, it also figures heavily in the Appendix A of LotR, so they could pull from that. Or they could go into more detail on the forging of the rings of power, the rise of the kingdom of Angmar and its battles with the Dúnedain. Eärnur fighting the Witch-King of Angmar and Glorfindel's prophecy could be epic. The history of the Dwarves and their ring of power could be interesting. I've felt for some while that the Battle of Azanulbizar wasn't done justice in Peter Jackson's adaptation of The Hobbit.
But with my luck, they'll probably make up a bunch of gritty shit to make it more GoT-like and introduce characters like Sexy Shelob. Plus, I'd have to subscribe to Prime, I can't fap to this!