@krlaframboise has an awesome implementation of how to handle all that in his [OBSOLETE] Simple Event Logger (Simple Event Logger). The logic is all on the Google JS side. But he has stopped supporting that app because of the breaking changes SmartThings is making to the platform. It would be possible to implement something that logic in this SmartApp.
Someone (I don’t think they are in this forum) has done something like that already. It is sitting in this pull request: Added ability to rotate to a new sheet each month by tsolid · Pull Request #7 · loverso-smartthings/googleDocsLogging · GitHub . His change makes it rotate automatically each month. I haven’t accepted that request yet because I’d prefer to make it optional (rather than every sheet splitting itself each month). You could try that version of the code.
Personally, I have one sheet of all my temperature data that used to fill up in 1.5 years, so I’ve been manually rotating it yearly for the last 4 years. Since I added 40 more Iris contact sensors earlier this year, it looks like it is now filling a sheet every 10 months, so now I’m rotating it every 6 months.