Wondering about LVPO’s like the Razor Gen3 that are getting up there in magnification and distance capabilities, is the image quite blurry when you start getting to 600+ yds? I believe that one has a 150yd fixed parallax. Does the blurryness go down if you decrease magnification? I suppose this is one of my concerns for going for these LVPO’s; if the high end isn’t very useable.

No, the image is clear out to distance.

I routinely shoot fixed parallax LPVOs out to 750y.  Can see the steel Buffalo @ 750 just as clear as I can with one of my scopes with adjustable parallax.

The compressed focal window and depth of field along g with the reticle drift you see in fixed high power target scopes is minimized by two things:

Lower magnification
Smaller objective lens

Most LPVO have both of those going for them. For example, my 4-16×50 had horrible parallax and focus issues at 10 yards. Cutting the magnification back to 8x or less made the target and reticle much more clear but it still moved lot. With a 24mm objective vs a 50mm one it would have cut my reticle drift by more than half. Usually, past a certain distance, you cant see well enough to notice a small amount of blurred target because you cant see the target that small very well anyway.