Why is my mobile logo on Turbo theme too small and grainy?

My logo is being exported as a transparent PNG at 72 dpi and the suggested 100 pixels wide. It looks grainy. Any suggestions? (white COGNATIVE MTB in the center to the right of the menu)

Welcome to shopify community.

Please share your store URL and if your store is password protected then please provide password too.

Thank you.

Let me know if this helps - https://g9369k0oumeneq7s-24747534.shopifypreview.com

Thanks!