Yes, you are correct - avoid the BR YVR-TPE since it is slopey seats.

AC's J ( other than the YVR-HKG flight) is just a touch below new BR in hard product,
and well superior to UA. Unless you are under 5'8", i recommend you stay away
from the AC YVR-HKG flight, since it is the high density version, with coffin C seats.