Increase VERTICAL distance between content of cell and its border?

Set the inset margin to zero and then try these methods:

Method 1:

1. Select the table cell.
2. In the Format inspector, click the Text tab and then click the Style button.
3. In the Alignment section, click the Middle vertical alignment button.

https://support.apple.com/en-ca/guide/pages/tanafea6d099/11.1/mac/1.0

Method 2:

Make the first paragraph in the table cell an empty paragraph. The second paragraph can be your data or sentence.