@Crazypedia I wish that there were more moderation tools! I'm wanting to make time just to make my own eventually.

If you only have CSS changes available, I'd try something like using the ::after() pseudo-element, hide the text with a font-size change, and bring it back in that element.

.compose-form__actions .button:not(.secondary-post-button){
  font-size:0;
}

.compose-form__actions .button:not(.secondary-post-button)::after{
  content: "Toot";
  font-size: 14px;
}