So, Rumple choosing to go for the Olympian crystal did seem the logical step if he (a) didn’t know a portal was being opened at the time and (b) has no faith that TLK will ever work for him and Belle.
Well a) he did know because he says “a portal” right before it opens and while your b) is true certainly it doesn’t help anyone to have the crystal but not the girl. Rumple needs more power, in his head, and surely there are other ways to get it; maybe not as fast or convenient as the crystal but there are other ways to get more power. But you can’t get another Belle. I just think the scene is meant to be read as a conflict, in that moment he actually had to stop and think about which one to chose, however he rationalizes it, he had to stop and think. And while he can say “I had to save the crystal to save Belle” it’s an excuse and somewhere, deep down inside, I think he knows it. Or maybe I still hope he does….
but even I can pretty much tell they’re just dragging out a Rumbelle TLK until Robert Carlyle leaves (which likely will be at the end of S6). While I don’t think Rumple really deserves to get Belle back after what he did to her, I do think the writers of the show will end Rumple’s final arc with a TLK. Probably Rumple will die in the end (since “villains don’t get happy endings”), but not before he saves Belle and their unborn child.
And that I agree with. I’m just not sure if it’s going to be fulfilling.