Could you ask this with a minimal REPRoducible EXample (reprex)? A reprex makes it much easier for others to understand your issue and figure out how to help.
For example,
- A snippet of your dataset would be helpful. How to do that.
- It's not clear to me what those columns are indicating.
- It would also be helpful to be a little more clear on what you mean by "annual buy and hold monthly return and sd" given the structure of the data.