I am happy to support Firefox by clicking on homepage ads. Right now, I can only see two. I would like to see 2 rows of them. Would it be possible to have a selector for the number of ads? This would also give more customisation to the button to enable ads.
However, I use the homepage shortcuts to visit websites from my history normally so having the ads in the same section would give me a hard time separating ads from history. Therefore, if possible, please show the rows for ads, then rows for the pinned shortcuts, then rows for history. Mark each section of rows with CSS so the users can navigate easily.
Finally, the positions of the shortcuts keep changing. If they always had the same position, that would make finding and clicking the shortcut easier for the user. For example, let's assume there is an advertisement shortcut for https://shop.mozilla.com/. Always show this advertisement in the second position so the user remembers its place and finds it easily.