@diezi Thank you for the in depth breakdown of how to change that! I found step 4 and on a little confusing so I didn't continue, but I didn't realize I could change the speed dial icon through the bookmark heart in the address bar. That was very helpful, and helped me change the icons enough to satisfy me for now.
I used to have a speed dial (I think it was through Chrome?) where you could setup a link for the speed dial, but use a separate link for the icon of the speed dial. It was all self contained and really easy to work with.
I'll also reiterate that the ability to adjust transparency for the speed dial icons would be a really neat quality of life touch that would appeal to those of us that really like to customize the look of things