IMO diving should be called as ungentlemanly conduct which is a cautionable (yellow card) offense. Way back in the day I was a FIFA certified referee for soccer. I officiated probably 100+ youth matches over a couple year period in the early 2000s and usually at the 14-16 age group club level (sometimes called "traveling"). There wasn't a problem with diving, and on the off-hand time it happened a quick "cut it out, next one is a yellow" was more than enough to prevent ever having to show a card. I am sure it's not called ungentlemanly conduct any more as that is not woke. But that's what it was called when I took the classes!