[gurabli]

I’m using one of these to do exactly what you want. Does DV and HDR+ perfectly fine.

This is really promising!
So I can have full everything for N2 to TV (like it was connected directly) and on Hdmi2 from splitter to AVR and enjoy DTS, TrueHD, DD+ etc. Sound really great.

Is HDMI-CEC (passtrough) also working?

And the harder part will be to get one in EU (although I see it is available on Amazon UK).

That's the device I bought on Amazon UK.  When I get a chance I'll check CEC.

Being able to program the device over USB can be very useful.

Many thanks! please, if you find some time, check the CEC. My Denon supports HDMI passtrough CEC perfectly. So I can use the TV with the Denon in standby, and have audio on TV. If needed, I just fire up the AVR and there goes the sound over AVR.
However, in this config, the splitter would pass HDMI to TV directly, and the AVR will only handle sound. Maybe no need for HDMI passtrough over AVR at all. So right now I think I need the following:

1. N2 connected to the splitter (4K, HDR+ and DV)
2.
a) Splitter HDMI OUT1 connected to TV -> passthrough 4k, HDR+, DV, CEC, everything, just as if the N2 would be connected to TV directly. So with AVR turned OFF, I control the TV and N2 with the TV remote using CEC, and have sound on TV. Like there is no AVR at all.
b) Splitter HDMI OUT2 connected to AVR -> passes sound to AVR (if AVR is turned ON) - I can have DTS, TrueHD, DD, DD+, everything the AVR supports. Ideally, if AVR is ON, CEC is also working, so I can control AVR using TV remote. The hdmi out signal to the AVR needs to be 1080, I guess, but doesn't matter at all, since image will go to TV over splitter's HDMI OUT1. AVR is not connected to TV at all. Or it can be, since I can connect Xbox 360 or other non-4K units to AVR, where no 4k/HDR6/DV is available, needed.