I think Yuuka pages are actually very smart, both as a filling and something to makes the situation more intensity. Like, you can put it in start of a chapter. Reiwa no Dara-san did it, in a very good way. Put it in the end would be very bad, as you want the end to be after resolve or as a high point. Putting it in the middle also make it seems long between each time Kuro wakes up. It also increase the curious for what happens next
Downside is, nobody f-ing care about Yuuka if they put her in out of nowhere like this