Calibrating your monitor is kinda difficult to do with just your eye and usually special equipment is involved.
Have a look here for a list of the most popular devices to help with calibration: https://www.creativebloq.com/features/best-monitor-calibrator
Also for eyeballing calibration have a look here: https://www.rtings.com/tv/learn/how-to-calibrate-your-tv (but not suggested)
The best method would be to find a professional to hire to calibrate your TV since they will charge you far less than buying the required equipment.
You can also try the settings that rtings.com have already made for your TV after calibrating: https://www.rtings.com/tv/reviews/samsung/q9fn-q9-q9f-qled-2018/settings
The above settings might not be the 100% best calibration for you but it will definitely be closer than the factory settings.
Thank you it's interesting
But which device is HDR compatible ? 12 BIT
4: 2: 2 ?
Is HDMI 2.1 compatible?
Or have to buy a new device every two years?
Do you need to take a device learning course?
Sorry I don't have experience myself with monitor calibration so I can't suggest a device.
But I know how the process works so I can answer that 4:2:2 and HDMI 2.1 is irrelevant to the calibration. These are just features that are bandwidth related. 4:2:2 compresses the signal in such way that HDMI 2.0b TVs can playback 10bit color +HDR in 4k@60Hz because of their limited HDMI bandwidth.
With HDMI 2.1 you don't need 4:2:2 anymore because you can playback 4k@120Hz 10bit +HDR at 4:4:4 (which is the same with RGB - uncompressed).
I don't believe that it's necesary for calibration devices to have HDMI 2.1 support. It's just a device that you connect to your HDMI port in the TV which has a camera and you hold the camera right in the center of your TV so that it can read back the colors that your TV produces.
Yes you will need to be trained in some way. You could read the manuals, watch youtube videos etc.. But it can get complicated.
I still suggest hiring a professional because those devices are expensive to buy yourself and use it just once on just one TV.