Looking for a Dot Product dot that is the right size

First of all, the Pages/Numbers/Keynote equation editors, do not give you full access to LaTeX, or LaTeX packages, even if you have MacTeX 2021 installed. That means many of the packages that might offer fine-tuning of a dot product symbolism are simply not available. See the About LaTeX and MathML support in Pages, Numbers, Keynote, and iBooks Author - Apple Support.

The equation editor in Pages (and Numbers/Keynote) uses a LaTeX/MathML converter (blahtex) that has a restricted vocabulary of LaTeX symbols that you can use, and when it is done, there is an embedded MathML object in your Pages document. There is a link to the blahtex PDF guide in the above link. That is the "bible" for inserting LaTeX equations in the mentioned applications.

You will have to live with \cdot if you plan to use the Pages, equation editor.

\nabla\cdot \overset{\rightarrow}{\textsf{E}} = \frac{\rho}{\varepsilon_0}

If you use that blahtex PDF guide that you have a link too within that About LaTeX link I provided earlier, it lists the LaTeX operators that it supports, such as \overset on page 4:

Apple has thus far assumed that users of the Pages equation editor are already familiar with LaTeX, or MathML, and that documentation resides on the Internet. However, the last word in support is what that blahtex translator will permit, and granted, that is frustrating… One has to know that \overset takes two arguments but that is not shown in the blahtex guide, and again, assumptions are running rampant that individuals just know LaTeX…