From what I grasp from this episode, the goal is still to rescue everybody from that "other" world beyond the hole. The author said multiple times that what Illya is looking for is a "true happy ending". Don't think that'll change. Hopefully it's just a question of how they'll get there in the end.
I'm fine with Shirou sacrificing himself in the end, if somebody ever needs to be sacrificed in the story. Seems to me that he should have died after sending Miyu away to Illyaverse (how can somebody survive after bearing the full wrath of AE lmao), and that would have been a perfect point for the story to end, without all the adventure of Illya-tachi in the Miyuverse. The fact that Miyu somehow came back to Miyuverse was already quite far-stretched. I think the author said that his original idea was really short, not much longer than two tankoubons. I guess the series became way too popular for either him or TM to not keep it rolling
The story development in the last few chapters felt a bit abrupt though. I wonder if it has something to do with the OVA that'll be released this year, actually. I couldn't find a natural point in the manga for the OVA to end, and it feels like this could well be an attempt to find an episodic ending and set the stage for the next phase of the story.