Wish they made it clear within the film itself that he didn’t really want the Jedi to end.
They did. He literally says it to Kylo at the close of their duel.
He’s angry and upset and he’s got an audience to vent to in Rey, so he’s trying to convince himself as much as he is trying to convince her that the last few years of his solitary life on this rock mean more than they actually do. His behaviors are saying just as much as any line of dialog would (and even then, he gets an actual line of dialog that makes it explicit later in the movie)
But it’s not an accident we see him carefully folding his Jedi robes, or that he’s still got a shrine with the Sacred Jedi Texts up and standing, or that he can’t make himself destroy the tree, and that he’s very upset at the possibility of Yoda having burned those books. All of those things are clear evidence that he’s not really dedicated to letting the Jedi end. He’s talking a good game but he hasn’t convinced himself, and every time push comes to shove he chooses to PROTECT the Jedi way, not destroy it. The very fact he chooses to train her at all speaks to the idea that he’s not convinced that it’s really “time for the Jedi to end.”
I mean before the duel, where he fully realizes that the Jedi shouldn’t come to an end after Yoda shows up and talks to him.