Here the SK6812 300leds 5 meters Raspberry PI3B+ 5V 10A power supply works very well, also with Netflix everything in HD (4K unfortunately not) also YouTube on Google TV Sony Bravia, Youtube app in Sony Bravia works well with Hyperion Android grabber,
Statelliet TV works via USB3.0 Video Capture card, Netflix in HD and Disney+ works on Nvidia Shield TV via the USB3.0 Video capture card, (without the USB 3.0 Video Capture card I have Netflix in 4K but no LEDs)
To get it working I placed a diode for the first LED see link: https://hackaday.com/2017/01/2…-to-use-a-3-3v-data-line/ this may not have been once needed.
GPIO10, SK6812 spi, SPI Pad 0.0 Baud Rate 3900000 and lastly
add spidev.bufsize=1024000 in /boot/cmdline.txt, which was set to 4096 instead of 1024000. After I increased the buffer, all LEDs worked properly instead of 1 or 3 or 10 LEDs and everything was white or flashing.
Once I had all the LEDs working, I only had to invert the colors red and green and cyan and magenta during image processing.
I hope it will help others and that it will work too.