WordPress/wp-includes/blocks/post-navigation-link/style-rtl.css

.wp-block-post-navigation-link .wp-block-post-navigation-link__arrow-previous{
  display:inline-block;
  margin-left:1ch;
}
.wp-block-post-navigation-link .wp-block-post-navigation-link__arrow-previous:not(.is-arrow-chevron){
  transform:scaleX(-1);;
}
.wp-block-post-navigation-link .wp-block-post-navigation-link__arrow-next{
  display:inline-block;
  margin-right:1ch;
}
.wp-block-post-navigation-link .wp-block-post-navigation-link__arrow-next:not(.is-arrow-chevron){
  transform:scaleX(-1);;
}