It also seems like there is no 3rd lengendary for a complementary version since Eternatus already got a story and a purpose in this game...

 

what kind of question is this? because it's a lazy and rushed game, done without much effort. that's it

 

how did hoopa / Volcanion tease the next generation?

 

this is actually quite true, it seriously saddens me, let's all go back to D/P/Pt days where we can glitch out and find darkrai, cresselia, shaymin, even though its cheating, it's still a lot of time and effort that still pays off.
Man, Game Freak needs to wake up.

 

Damn, Truely good old times, then you show them to your friends and they be shocked as fuck and do everything so you want to trade with them and give it to them lmao

 

So you’ll be forced to buy Ultra Sword and Ultra Shield

 

There is, it's just a secret so we don't know about it :v

 

Most likely this.

Even if they plan to do that it would make sense to not add that content to the game until later to avoid datamining, which inevitably always happens. You might be forgetting that game updates/DLC on the Switch are easier and more convenient than ever, and maybe Game Freak will finally take advantage of that. I kind of doubt it though.
It would also allow them to release the game sooner and work on the extra content after release.

 

Utra Great Sword

 

Of course it wouldn't be a secret if it was in the game because dataminers exist. They will show up in updates.