I will rewatch the opening of X when I have time. If it was destroyed by the experiment, you'd have a point.
Right now I'm looking at things from the pov where aliens destroyed earth. BUT: that doesn't mean there can't be a connection.
It's too much too explain it quickly, but: are you knowledgeable about upper/lower realm and real numbers domain/imaginary numbers domain? That's Takahashi Tetsuya's grand underlying concept for xenosaga/xenogears and it's likely part of Xenoblade, too, because it's part of Takahashi's philosophy, not just a game idea.
Using that connections are well possible, albeit still complicated in how exactly it works. From how I understand, Xenoblade 1 is part of the real numbers domain (rnd) whereas Xenoblade 2 is in the imaginary numbers domain (ind). Xenoblade X also is part of the ind, it's basically the future of Xenoblade 2. And now we have Future Connected that shows a rip in spacetime potentially leading to a different domain and time.
It's complicated, especially because Takahashi has only been hinting in each game at such concepts. That's why I hope for Xenoblade 3 to drop the charade and delve fully into these philosophical, metaphysical matters. Let's follow Klaus on a journey through space to explore the conduit/zohar and lastly the upper realm, too.
Sorry if you don't understand a word I wrote xD
EDIT:
And now i researched telethia in Xenoblade X. Apparently there's 2 (one with another form), but only one is listed in the game's bestiary, the other seems to be a multiplayer event. So we're still at one officially recognized Telethia. And as for a connection to Xenoblade 1, there's this:
"As revealed in one of the possible paths of
A Fateful Choice, the
Orphean once encountered Telethia at a vast ocean in another world, in poorly-understood prehistoric memories only recalled through the Ovah of Orphean female betaforms"
Vast ocean and 'prehistoric'? That's almost a confirmation imo