Well, if you go right you'll miss out on Mommy 4ths sweet embrace along with being related to Aglaecwif.
After this update, MC would be related to Aglaecwif regardless of what he chose because of Syla.
Before the update:
MC would be Aglaecwif's brother, if the 4th is chosen.
After this update:
MC is potentially Aglaecwif's nephew and brother, if you choose the 4th.
If you choose the 3rd, you're Aglaecwif's nephew and cousin.
Hell, now MC's own mom is his sister. Since Syla claims to be the 4th's daughter. We focused on the 4th being his grandma, we forgot that now his mom is his sister too.
The incest is actually crazy. Since Aglaecwif is now his aunt and sister, their child is going to be his cousin/nephew or niece/son or daughter all at once. This is the most blatant display of an incest family tree in the game so far. Though, the 4th giving him a blowjob at the beginning would definitely qualify as incest after this update. Especially since she was his "grandma" already before the infection even happened.