Is there any issue between Video Color Space 601&709 - partial&full?

[2Lei]

Hello peeps. Like my title saying, I've noticed some kind of visual improve in my streams(twitch affiliate) when I have color space 601 partial active, instead of bad..pixelated video when I choose 709 full or parial. Although now is not that often, I still get pixelated video and webcam. Is there someone who can explain why is there a visual improve and what can I do in order to have a clean stream?
My stream rig is:

1. CPU - Ryzen 9 - 5950x 16 cores, 32 threads
2. RAM 64GB 3200
3. GPU RTX 3090 founders edition

Someone from this forum told me that visuals are getting improved by setting a high bitrate. As we all know that twitch dose not allow more then 6000kbs I've tested on youtube streaming with 50000kbs and the video was .... deplorable. Actual worse then on twitch. Also, tested on a second test twitch account setting with 12000kbs. All my tests, playing fps games like valorant or pubg where kinda pixelated when high movement. I don't know about you, but I say my rig can and must handle high streaming without having pixelated video.

I also stream with nvenc(new), KeyFrame Interval 2, Preset Max Quality, Profile High, Look-ahead and Psycho Visual Tuning checked*(if I uncheck those I get more pixelated video), GPU 0 and max B-frames 4.
I tried all kind of tests changing settings, also changing on x264 on slow. I always get pixelated video and webcam when I do fast movement. Streaming on 720p at 60 or 30fps, did not change anything in the pixelated video and webcam issue. I still got them.

I will post a screen capture on how my stream is.. bad and pixelated with EVERY single obs setting set as high as it can get. And I cannot understand why is this possible with this very high end pc.

ps1. My GPU is always in the 50%/60% and never over 70 ° celsius.
ps2. My internet is gigabit so I have a 900dl and 800ul speed.

I hope with all this, someone can and will help me understand what is wrong with my stream. Thanks in advance