Here's a pic of the dipstick I found on Amazon. They say it's for the Mercedes Benz 722.6, 722.7, 722.8,or 722.9:
Seems like a superior design. But looks too long in the photos to be usable in a 722.3.
This E-Bay listing mentions 1220 mm. That's 48 inches. At that price, I'm almost inclined to see if there's any way I could attach it to the top part of my ruined, now replaced dipstick. Finding the correct length might be dicey. One thought is to approximate the length from the original and put a small vice-grip at the spot and get the level right based on the original and then put the donor device in and adjust until the right spot is found. I dunno, maybe. Another project on the back burner.
https://www.ebay.com/i/191939197679?chn=ps