Is there any way to add text ABOVE the images?

Hello,

Thank you for choosing our plugin.

Please check this guide https://supsystic.com/documentation/how-to-make-rounded-gallery-with-captions-under-images/.
Please use this CSS rule

<style>
.grid-gallery-caption[data-grid-gallery-type="polaroid"] figcaption{
position: absolute !important;
}
</style>

instead of CSS used in step 6.
You can add it into HTML block if you use Gutenberg editor
https://www.dropbox.com/s/i91u8jdk8dcuqu2/Screenshot_10.png?dl=0

Please purge all website’s caches and clear browser’s cache after saving settings before checking result.

Best regards,
https://supsystic.com
Dante