So Luke isn’t a dream but he doesn’t burn down the tree, the jedi order doesn’t need to end and yoda doesn’t even appear. He just hesitates to train Rey as part of a test. And still saves the day on crait. Similar to how Yoda didn’t fight in Empire; he trained Luke to fight.

Or maybe, after Luke saves the day, he then sees Yoda, who tells him that Rey has everything she needs going forward. Then Luke dies.

After Rey moves the boulders on crait, she no longer is tempted to the dark side. The big thing is Snoke/Palp are a dream. The other battles remain the same - First Order vs Resistance.