VLC Takes CPU instead of GPU

i am trying to play 64 IP Camera stream ( D1 Stream) with below cpu Configuration i7 10th Gen CPU, 32 GB Ram, 16GB Nvidea RTX A4000 Graphic Card.

Behaviour

when i am playing 64 stream GPU memory used- 2.8GB/16GB and CPU Used is 90% tried everything but still cpu usage is high but GPU memory not utilized. Expected: first GPU memory should consume after that CPU memory should use.

using LibVLCSharp latest Version - 3.6.7

this issue is coming from last few year as i seen so many people have reported this.