How do I Interpret Heart Rate Variability (HRV) Data?

I understand what Heart Rate Variability is, but I do not understand if higher HRV in milliseconds indicates healthy HRV or if lower HRV in milliseconds is better.

For example, today, my HRV average was 28ms. Is this better than 30ms but not as good as 26ms? Or would 30ms be better than 28ms?

I have an Apple Watch 4 (Nike edition).

Tks,

Eric