I thought the same about my Onkyo AVR which state at the website “This Onkyo AVR enables transmission of High Dynamic Range (HDR) formats…” So it should be able to passthrough HDR formats such as at least HDR10 and HLG. I’ve sent Onkyo an email to clarify this.
At least your results look similar to mine and I bet that you’ll get “Hybrif Log-Gamma: 1” and EOTF: HLG as I did when you connect N2 directly to your TV.