For this, you need to add the color in Info.plist.

<dict>
 <key>CFBundlePrimaryIcon</key>
 <dict>
     <key>NSAppIconActionTintColorName</key>
     <string>CustomTintColor</string>
     <key>NSAppIconComplementingColorNames</key>
     <array>
         <string>BackgroundGradientColor1</string>
         <string>BackgroundGradientColor2</string>
     </array>
</dict>

Apple Official Documentation: https://developer.apple.com/documentation/bundleresources/information-property-list/cfbundleicons/cfbundleprimaryicon/nsappiconcomplementingcolornames