grammatical number - Point[s] of datum vs. point[s] of data

I know that there's no any shortage of controversy about "data" and "datum", but I've recently questioned the validity in the specific case of "I am but a point of data". Is this, under the strict definition of datum and data, grammatically correct, or is "I am but a point of datum" technically better?

I'm torn, because while the former sounds more correct from sheer popularity, in the seemingly analogous case "I am but a piece of pie", "pie" remains singular.

Additionally, if these cases are indeed analogous, shouldn't "We are but points of data" be corrected to "We are but points of datum"? Returning to the analogy: while "We are but pieces of pies" is grammatically valid, it implies something different than: "We are but pieces of pie" which feels closer to the singular.