It kind of irks me to be spoken for, so to say, so just for the record: me right here, I wear dresses, and I especially like to wear long ones. We do exist!

Also, any inconvenience is a worthy trade-off for vastly minimised accidental flashing risks, for me personally. I like dresses, but I'm not always good at remembering I'm wearing one 😅

No offense, but I'd say your claim of 'not uncommon' is rather inaccurate, and with an additional 'r' at the end, that would be even fewer people. Honestly, in all my life I've neither met nor heard of someone named either variant. (Though for the first one, a quick wikipedia search brings up two apparently-notable-enough people, a quick general search suggests overall it's less than 500 out of the 84 million Germans. No result for the r-variant, and one news story about a guy struggling with his name being the German equivalent.)

I suppose "Niggemann" or similar would be more common, but also not terribly so, from my experience.