Its just me or the 60 kills method dont work?

I only hunted one shiny without sandwich, just shiny charm. it was a rotom, terrible spot to hunt, only 5-6 rotom spawn per picnic reset.
felt terrible, took me around 4 hours after 60 killed.

Its much easy with sandwich? How many shinies you get with sandwich?

I personally have found a couple shinies with this method on outbreaks, both under 10 picnic resets. But I've also been trying to hunt a Mankey with the same method without using outbreaks, just encounter sandwiches, and still no luck.

Shiny charm, but no shiny sandwiches.

I just got a chancey on my first exp run today. No charm
On ham sandwich.