I appreciate your thoughtful discussion in the most recent Story and Star Wars re: Luke's being cut off from / reconnected to the Force. FWIW, this is one of the few areas in which the TLJ novelization provides additional insight.
According to the novelization, Luke proactively cuts himself off from the Force and, after the Third Lesson (which is included in the novel), proactively reconnects to the Force by "reaching out" the same way in which he instructed Rey to feel the Force. That's the moment at which Leia awakes from her coma, uttering, "Luke," which I believe is included in the movie - but maybe I need a re-watch to be sure!
Either way, the first evidence we have in the movie that Luke has reconnected with the Force actually comes before he levi-stops his fall. It is when he walks in on Rey communing with Kylo and Force blows up the hut with his reaction. In the novelization, he had been coming to the hut to tell Rey that he had reconnected with the Force and would return with her to join the rebellion.
You may debate, of course, whether the novelization of the movie is canon per se and, even if so, everyone is, of course, entitled to her own head canon. To me, the question of Luke's agency in being cut off or cutting himself off comes down to characterization. Is this the bad ass Master of the Force we know from the end of Return of the Jedi? Or is this the whiny brat who wants to go to Toshe Station to pick up some power converters and sulk about going nowhere? I find it more coherent that the former might be cut off from the Force due to his devastation while the latter might cut himself off as a way of "taking his toys and going home."
Regardless of which you choose to believe in your own head canon, something I liked about TLJ was the reminder that those two versions of Luke are part of the same character. It's a reminder that all of our heroes - both mythological and IRL - are complex, flawed individuals. We need to remind ourselves of that before we follow them blindly but we (and they) also need to remind themselves that flaws and failures are OK. When we learn from them, we can walk out with a laser sword and face down the entire First Order!