Sorry, but you first talk about grade 1 monitors and then when I show you spec which defines them you cherry pick parameters from it
(I don't care about tally light etc, but picture parameters).
You still seems to miss my point that EBU spec is one thing and real world is slightly different and monitor manufactures not exactly follow it (hence I called it recommendation but you don't agree with this wording). Eg. Panasonic panel is good, but angles are rather poor, but we can live with it in real world (seat directly). If you follow EBU spec then it's not grade 1, but real life treats it this way (which I think is ok).
Have you seen single Orion monitor as I never even heard of it. Maybe it's good, don't know.
I see no reference to EBU and never seen Sony quoting it (like Orion does which is a proper way).
Some good OLED may now (finally) meet EBU spec although you would still have to properly check it as things as angles restrictions are not so obvious. I think there are quite few SDR monitors which can be treated as reference for SDR and they don't have to be that expensive as you said.
Reference HDR today is either Sony X300 or monitors using Panasonic panel (assuming they are done well, like Sony, Eizo even if they have fairly bad angles). For me all others don't deserve HDR reference badge (there are also Dolby but this is not easily available, so I skipped it).
Also EBU is broadcasting body and post is a wider industry and those 2 worlds sometimes operate very differently. Where broadcast uses heavily compressed XDCAM format, high-end post operates on EXR.