She thought she could turn Ben back but she was wrong, she got tortured, came close to death and her lightsaber was destroyed before she managed to escape. Luke might have lost a hand in ESB but he got a new one before the movie even ends, let's not pretend it was something particularly earth-shattering.
Doesn't the fact that she tried to turn Ben once again, when Han already failed and Luke insists that it can't be done, show that she made a big mistake? What would have been an appropriate consequence to her bad decisions for you? She failed in her mission to turn Ben and instead of him dismantling the First Order she had to run off and stop him from erasing the Resistance forever.
Alright, I guess it's more about the presentation for me.
So in ESB the point was that Luke shouldn't go back to face Vader because a) he should stay and complete his training b) he wouldn't win anyway - in short, it's a trap. What does the little goofy Luke do? He faces Vader and gets his ass kicked. Vader plays with him, throws stuff with, handily beats him, and cuts his hand off. It's clear that Vader has the upper hand. Luke then loses, literally falls down, and by sheer luck gets saved by the others like the little bitch he is. Han is in carbonite, and the rebellion was destroyed (or made to flee) from Hoth - the situation is dire for the good guys.
TLJ has a similar premise. Rey wants to learn from Luke, who tells him that Ben can't be saved and that it's pointless. She goes anyway and springs Snoke's trap. She however doesn't really suffer (she gets tortured for literally less than a minute) and beats all the guard and faces off Ren. She escapes, saves the Resistance in a hero pose and they all fly off. The Resistance, just like in TFA, is just a small group of people trying to save the universe... once more.
What do I have in mind? I don't know, haven't really though about it, but maybe don't let her escape as easily. Or maybe she doesn't get to rest and is stranded somewhere on her own while the others just narrowly escape the FO. Or maybe she gets captured by the FO even. Just make one of her bad decisions have a consequence. Yes, she realised that she made a mistake, but that's not really a consequence. I just think that in the end all things kind of worked out for her, which just isn't as interesting imo.