T3 Blot Fishgoat is ridiculously hard to hunt

I have spent hours trying to get even one kill of Blot, the Fishgoat in a 220 ascended herbarium realm. Even with 3,600 stealth AND crouching the whole time he seems to notice me, even when I'm further out than 100 meters. I have tried multiple times. I've been able to get him a few times, but it usually is an entire afternoon wasted on this frustrating thing. I think a little balance is needed at least on this one fabled creature. For one thing, it doesn't seem fair that he can move entirely off the map. I love Nightingale otherwise and have played for over 700 hours. This just sticks out as stupidly difficult.