Is there literally an almost 10x difference in the number of full cycles? Where can I read more about this?
I really wish cell phones and computers came with an adjustment to max cell voltage. Cutting even 10% capacity can double your cycle life. Some do, but it's a hodgepodge and not standard.
https://batteryuniversity.com/article/bu-808-how-to-prolong-...
Having said that, this resource does not seem to support the magnitude of the numbers in LeifCarrotson's comment that I was replying to. First, I did not see a relationship between voltage and Depth of Discharge (seems unlikely to be linear, especially given table 4), which is what the page seems to mostly talk about. Second, comparing 4.2V to 4.0V in table 4 suggests a 4x difference in the number of cycles, not a ~10x difference. Figure 6 also seems relevant and suggests maybe a 2x difference.
Pull 4x from one table and 2-3x from another and it would probably put you somewhere in the 10x range. Though I'm not sure it would be strictly multiplicative.