Hello,
Sorry to say but for the Share Buttons under the Single Blog Post, there isn’t a separate option for color changing. They pick their original social media platform colors predefined under the Theme: https://snipboard.io/zDteZv.jpg
So, if you want to change their colors, then Custom CSS would be required for it.
Like for an example, according to the provided Screenshot. For the Twitter & WhatsApp, you can try using the following Custom CSS code and paste it to Dashboard >> Theme Settings >> Custom CSS >> Global CSS section:
.social-whatsapp { --social-color: #23ba37 !important; }
.social-twitter { --social-color: cyan !important; }
The Colors written in it are just added exemplary, you can write your own color hex code or color name.
Best Regards