For ME with my standard scope, no turrets, probably 400yds with my .300WM. For many with more advanced scopes, 600+ yards. From sticks, no bench and the animals are moving for the most part because it’s a DIY hunt on public land and other hunters are pursuing them. When your target stops, you have a few seconds to take the shot. I’m really not that proficient at anything over 300yds given that reality. I don’t use sticks when elk hunting because where/how I hunt they’res no time. Different hunting environment than my one PG African hunt.
When I read your question, I took it as the type of field conditions like we watched in the video. The scenario you just laid out is very different. This is a "condition", one that will limit the distance you can shoot accurately. I do feel I could use my viper-flex-styx in that situation. I shot my Zebra just inside of 300 yards moving up the side of a hill with my 375h&h. Have a 1.7x10 scope on it, that was more than adequate. I would more apprehensive further than that with those sticks (500 with a 7mm is probably my limit unless I trained a lot), only because I have not used them much further than that. Especially when we are talking about a 9#375 vs a 20# 6mm. Have shot off of all different types of objects in comps much further. Different gun for a different game. When shooting off sticks, you still have to drive the rifle. The bigger the recoil the harder to drive.
If we are talking about the ability to go prone, well I have shot targets over a mile with 22X scopes. I do enjoy my magnification the older I get. Probably why I like my 4X40 on my 22lr.