Shoot at the natural respiratory pause at the bottom of your breath before you inhale again.
Your sights should settle down onto tgt at bottom of exhale.
Bout the only thing you will deal with if done properly is sight or reticle bounce from your heartbeat.

2 to 4 seconds before your heart will race a little and vision blur.
If it starts.
Do another 2 to 3 breathing cycles and then exhale ,sights settle and squeeze.

Holding your breath with lungs full or half full or empty of air for 8 to 10 seconds is the wrong approach.


Ymmv.....