I understand why people think that this is a whole other dude. I think the change was quite abrupt too but I believe it's the way the seme was drawn. The seme was quite kind to the uke for a lot of chapters now but his kindness is so susp because of how his face expressions are drawn lmao. Now, he is drawn more innocently
I love how random this manga. The situation always turn more wholesome than expected. I bet that aniki just gives instructions to Sora but Sora is the kind of person that takes them seriously af. I think this is a whole misunderstanding.