Set up collection color swatch filters

You can enable color swatches as filters by following the steps bellow:

You need the "Shopify Search & Discovery" app installed to add and remove filters, themes in the Shopify Theme Store use filters in the same way.
"Shopify Search & Discovery" is the official app of Shopify and you can use it with confidence.
The Shopify Search & Discovery app gives you more control over how customers discover your products online.

1. Add filters

2.Checked the ‘Show filter color swatch’ setting in collection template

3.Uploading custom color for color swatch

https://themegoal.com/products/uploading-custom-color-for-color-swatch