So conceptually you have a row with two (or more) columns.

STEP 1: In the row settings you make sure the “Equalize Column Heights” is enabled

Equalize Column Heights Divi, Vertically Center elements in a column

STEP 2: Within the same Row settings, go to the specific column settings of the module you want to be centered horizontally.

Within the same Row settings, go to the specific column settings of the module you want to be centered horizontally.
Enter "margin:auto;" in the Custom Css of the "Main Element" section.
Enter “margin:auto;” in the Custom Css of the “Main Element” section.