It will be interesting to see whether she decides to pursue him, or leave it up to fate. There's beauty in the ephemeral nature of their coming together and parting ways, but it's a bittersweet one--and while Chokki is well-versed in the 'romance" of the world and all the little things others often miss, she's wholly unfamiliar with the romance found in sharing those things with someone who's as bought-in as she is.
Shun's turned her largely-solitary world upside down, and even as she's gotten to show him so much, in turn he's showed her how much more meaningful things can be when experienced with another like-minded soul.
Shun's very much come to enjoy his time with Chokki. He does like her--whether he's fully cognizant of that fact or not could be argued, as we've not gotten explicitly stated confirmation (that I can recall, anyway). But he's also his own person, and he's rediscovering things that he once held close to his heart--but he did so because he got back up and started moving forward after his injury.
He owes that, in large part, to Chokki.
So to that end--even if he went back to sports, it's hard to imagine him wanting to end what they have. Even if he joined an actual club--there's nothing saying it'd take all of his time. They would have to work for it, but the "Hyper Go Home Club" would just become "Chokki & Shun Hyper Dates", in effect.
Plus, there's the point after she graduates. Shun will be on his own as a 3rd year in that school--I kinda suspect that he'd join a sports club at that point, because who else would he share the HGHC with? Who would he even want to share it with, other than Chokki?
Chokki's stuck thinking about where they stand here and now. And that makes sense--she just watched Shun literally run off, and she feels their time growing more and more constrained, as she worries over whether she's been holding him back all this time.
She saw the face he made, the 'peace sign', and that layered over the photo she saw at his home makes it clear she's realizing who he once was (the Young Shun she envied over never getting to know), and now she sees a future where he goes back to that--and leaves her behind.
But we know at least some of Shun's mind. The clock's ticking for them, but they've navigated a lot together, as has the author with this series in general.
I'm confident that even if this concludes shortly after a declaration from them both, it won't be handled anything less than splendidly.
Thanks for the TL