Shakyamuni Buddha recommended a path of Dhyana (Zen) plus Direct Inquiry and Analysis.
As Shakyamuni was dying he refused to name a lineage successor. Instead, he said the Dharma was his successor, and that students should "Be a light for yourselves, go all out, work hard, attain liberation."
THIS would seem to settle all questions about which lineage is the right one, which teaching is the right one.
As for teachings, the Dharma is not a teaching, it's just Reality as revealed by Dhyana (Zen) and Direct Inquiry and Analysis.
No Self, No Lasting Phenomena. Clinging to what doesn't exist or last causes anguish. Releasing oneself from such clinging is Cessation of Anguish (Nirvana)!
What's the problem? This is simple. Anyone can do it. Ambitious people are at a disadvantage.
"Delightful is the Dharma. Delightful in the beginning, delightful in the middle, delightful at the end."
Let's do it! What fucking horseshit all the arguments and disputes are. If you're truly pursuing Dhyana plus Direct Inquiry you have no time for throwing your intellectual weight around or playing "Buddhist" games.