You are the one confusing it.
Yoda states that Qui-Gon learned the path back AFTER he diedSimple stuff.
Isn’t it a little too late to learn to the path to immortality after you’ve already died?
Apparently not in this fantasy setting, as Yoda says earlier in ROTS that the dead “transform into the force”.
Not any more out there than Gandalf getting sent back by Eru(?) if you ask me.