[Newbie] N100 + TrueNAS Hardware Encoding problem

[FlyYF]

Hello everyone,
I have a problem basically similar to that forum post (which has been aborted, user not being here).

Basically, I own a new TrueNAS Scale 24.10 server (on an Intel N100 board. The N100 is supposed to have an iGPU that is supposed to transcode even AV1).

I noticed that some HDR videos were running slowly, while troubleshooting, I assumed it was due to the fact that TrueNAS/Jellyfin is not using the IGPU and hardware acceleration properly to transcode.

I then, went back to my Jellyfin installation, toggling that box here    

Then, I've been setting up my jellyfin that way    

I assume that my set up is not finished (I don't know how to fill "QSV Device" for example).
Please be kind as i'm quite newbie both on Jellyfin and on TrueNAS
1) Am I assuming right ?
2) Could you explain me what I did wrong ?
3) If there's any driver to install, could you explain me gently how to do considering i'm totally newbie and I spent 4 days trying to make that NAS work ?

Please find my ffmpeg logs here: pastebin.com/5AtxRPDJ