I have a NZXT Kraken Elite IO cooler.
Where is the Kraken's pump connected on the motherboard. I've not used an AIO, preferring big air coolers, but my understanding is the pump motor should be run at full speed (constant +12V) whilst the radiator fan speed is controlled by the CPU temperature. Please correct me if I'm wrong.
Check which headers the pump and radiator fans are connected to on the motherboard. If you have headers marked Pump and CPU_Fan, it's a fair bet you should be using them. Check the fan speed profiles, especially that of the pump. If necessary, set the pump to full speed at all temperratures and see what happens.
I used the one that was already on the pump
If the block housing the pump came with pre-applied thermal paste, that should be fine. No point in adding more paste. It will simply make things worse. Too much paste is just as bad as too little paste. There's a happy medium regarding paste thickness.
If I start watching a Youtube Video the usage gets up to over 25% with a temp of 70°.
Is that normal or what could be the Problem
Just for reference, my 7950X sits in the mid eighties when running hard and all cores peak at 95 degrees from time to time. Ryzens can run hot with no problems.