My case is resolved now after assist from friends at Reddit. I bought my Lumix S5iiX in September 2024 from Norways biggest reseller. For this question they could not help me, but recommended Atomos support. That says a lot. This morning, I have executed successful tests (almost). Yes, the footage is now stored at my AtomX disc. But I still have two questions and a friendly «nag» towards Lumix. On the S5iiX I configured two different compressions: 1) ProRes 422HQ 1920x1080 with 50fps - the only choice 2) Full frame MOV LongGOP 3840x2160 422 10bit 25fps. (I prefer 25fps). In the menu, choose cogwheel , InOut, HDMI Rec Output, Info Display OFF, HDMI Recording Control ON, Sound Output ON, Enlarged Live Display Mode1. In the menu only SSD, slot 1/2 is visible, but I guess SSD means the AtomX SSD as long it is connected with the HDMI and not with a Samsung T7 over USB-C. On the Ninja however, only ProRes compression is available, amongst DNxHR and ProResRAW. However, what I can see on my Mac mini with FCP is that it retain the 3840x2160 resolution when I output LongGOP. Very satisfying. So back to my «nag». Even my professional reseller could not help me. Coming from my Canon EOS 5Dii (a 2008 camera), I am used to turn the Mode dial to what I need. I understand that the S5iiX is a complete different bull. When you turn the Mode dial to CinemaM, video is just half the story. Yes, you then can choose you preffered format, to SDXC slot 1/2. If you want to use SSD over the USB-C port, choose another menu. If you need ProResRAW, choose another menu (and you the can choose different formats under the RAW segment). So, if you need to shoot video compressed, choose a third menu, configure your Ninja (V or not) to the correct compression, MP4 is not supported and that is OK. Nothing of this is described as easily understandable summaries at either Atomos or Lumix. Even my supplier does not know! So what I question is if it is possible to make a summary of the different options if you either turn the Mode dial to CinemaM, or if you organize all the different choices under ONE main menu choice. As the case is today, it’s like have a Greek Gyros served in front of you and you ask how the chef has put your meal so delicious together. Sorry Man, the Chef is not available. The key challenge for me (and my reseller ) is that the choices are smudged and hidden. You need to know! The other issue is the stress- factor. How many times have you experienced that you used wrong settings or forgot to choose the correct values on the set. You was stressed or simply forgot. In my opinion Lumix has a potential to make the menu choices more understandable and in addition add a summary in their camera manuals for this spesific task. Back to the Chef: what is the ingredients, for how long do you cook, how do you combine? After much struggle and good assist (from Reddit, not my reseller) I think my troubles are over for now. But does it need to be that hard? Anyways, I have learned a lot.