🤔 Perhaps you could instead use a custom classname to specify which group you would like to remove the icons from.
For example give the group you would like to remove icons from the classname, "buttonizer-no-icons".
Then the new custom CSS should look like this:
.buttonizer.buttonizer-no-icons .buttonizer-button:not(.buttonizer-head) i, .buttonizer.buttonizer-no-icons .buttonizer-button:not(.buttonizer-head) img, .buttonizer.buttonizer-no-icons .buttonizer-button:not(.buttonizer-head) svg {
display: none !important;
}