How to make pixel perfect model

I'm learning computer vision

I built a hybrid person segmentation model using: DarkNet21 as backbone FPN Transformer Decoder

Used BCE + Dice

Trying to train it from scratch

It's good but not pixel perfect

It's like 95% accurate

just very small percentage that might fix it

I'm using p3m 10k dataset and Supervisely Person Clean

Repo Link: https://github.com/mohamed-naser-awd/hybrid-segmentation-model

Any ideas what to do?