It’s showing completed but it’s evident that there are remaining chapters.😞😞😞...

I know it's not really helpful at this point to say, but it being marked as completed just means the mangaka isn't making more of it, not that all the chapters have been either scanlated or posted.

I feel your pain, though. These two are adorable, and I *really* want to see Yuki facing what happened to him in Italy. I want to know exactly who hurt my baby and how they did it, and I want to see them get their just desserts.