Sam, you haven’t answered a single one of ujm’s taanos which the Torah world has on modern orthodoxy/some OOT. Instead, you reductively state that the only difference is whether or not you hold of rabbeinu tam for ending shabbos; I’m guessing you believe the difference also to be whether or not one eats gebrokts, since there are differing customs in that regard as well.
Modern orrhodoxy doesn’t merely adhere to one authority or minhag which is more meikil. German Jews are “meikil” in halacha more than others, but are very medakdek in halacha just as any other Torah community. Chasidim are known to be even more lenient in halacha, yet have high standards in mussar and hashkofa.
“Not being Torah focused” is a huge deal, and it’s a lot more than if you end shabbos according to the Gra or Rabeinu Tam.