It sounds like what is sought after is a matter of wants and not needs.
Honestly, if you re evaluate your want list to fall more in line with what is really needed to shoot 300 yards at a range, you could broaden your choices and save yourself some money.
You just plain don't need a first focal plane milling reticle to shoot 300 yards. Besides, it's much easier and cheaper to get optical quality out of a second focal plane scope than it is a first focal plane scope. Honestly, I prefer to shoot with my Gen 2 PST over my PLXc.
If you delete the need for a ffp milling reticle, you can save $1k or more.
Vortex Razor 1-6x, Vortex PST, Trijicon Credo HX, Delta Stryker 1-6x, PLXc Nova, etc.
I have to comment on the NX8 1-8x. I just switched from an NX8 1-8x with DMx reticle to a PLXc Griffin Mil on my humping around rifle and I regret it.
Yes, the PLXc has better optical performance and would make a better (not ideal) range optic, but its build seems to lack robustness and doesn't inspire confidence, although this is likely a non issue on a range rifle.
The NX8 comes across as a purpose built optic. You put it on your rifle, carry it around and when you need to shoot, it does its job. It's small, light and it's feel inspires confidence.
There was an interesting point that grabbed my attention. Neither the NX8 nor the PLXc came with ring torque specs. The mount i use specs ring torque at 28 in-lbs.
When i called nightforce and asked them what the ring torque spec was on the NX8, I was told to use whatever specs the mount instructions say to use. This would indicate to me a confidence in the build quality of the NX8.
When I reached out to primary arms, I was given a BS answer. They said that the spec on their PLX mount is 16-18 in-lbs and that while that would be the most appropriate SUGGESTION, they cannot guarantee the compatibility of their scooe with other mounts. How do you like that for an answer?
Still, if you want to stay in the realm of ffp, milling reticles, I'd go with the ATACR. Unfortunately, when considering scopes, all most can do is go to the store, check them out and try to figure what would be best for them. The only real way to know is to mount it up and run it. I think the best advise would be to buy used so you don't take a beating on whatever you buy if you discover it ain't for you.
This may be off the wall, but have you considered something like a 3.5x acog with a piggyback red dot? Good glass. Really good glass. I have one on my 12.5 and when I compare it to my PLXc on 4x, the ACOG trounces on the PLXc in terms of everything. Optical quality, field of view, depth of field, light gathering, etc. And the image is just beautiful.