Kawaki Uzumaki. So Boruto has a new boyfriend. Gay.
That was a bad attempt at throwing shade considering that there are many reasons as to why someone would have the same last name as you, such as:
Familial relationship
Adoption into a family (which is basically what's going on btw)
Sheer coincidence
Marriage
Etc...
Also, Boruto is not the only Uzumaki. If Kawaki had to be someone's boyfriend, he could be Himawari's and still get the name upon marrying her (and before you say that Himawari is a female and that Kawaki wouldn't get the name because of that, remember that Sai didn't have a last name, so he took Ino's upon marrying her. Kawaki as of now does not have an established last name, so he could take Himawari's).
Bad attempt at shade. You can do better than that.
OT:
Naruto was stupid for taking Kawaki into his house without considering the danger he could pose to Hinata and Himawari, as well as to the family property! It would be one thing if Naruto still lived alone, but Naruto has a family now, and he didn't even consider how the other residents of the house may feel!
Konoha has an orphanage! Naruto should have sent Kawaki to Kabuto! Plus, SM Kabuto and a bunch of MS users could probably take care of Kawaki if he got out of line!