I do find it interesting that fuckboi has not appeared at all, like you said, Sakura hasn't even mentioned fuckboi as her new lover, if Airi really wanted to cement Sakura as not ever having another postive moment with Shinobu then fuckboi would have gotten another sex scene that made clear it was in the present.
Because so far, I'm still under the belief that 131 was just part of 129, that is to say, Sakura and fuckboi have only fucked once.
The very fact that Sakura is still thinking about Shinobu at all means fuckboi hasn't overwritten her mind completely, some people might argue fuckboi's absence is because he's on another movie but I think fuckboi is absent for that reason AND because it's intentional by Airi.
Fuckboi got what he wanted out of Sakura, he fucked her and made her break up with his boyfriend, he's onto a new movie and a new conquest, I gurantee you that when we see fuckboi again, Sakura is going to be conflicted about having sex for a movie scene and fuckboi will just go "lmao just do it, you're an actor aren't you?" it will be completely cold devoid of care.
On the otherhand, fuckboi could go the cuck route and simply "fail" to stop Sakura from getting into sexual situations.