What do the different dates in a TCDS mean?

The Type Certificate document is just a kind of diploma so to speak, or, as it says in its name, a Certificate. The real meat is in the TCDS, which describes the technical details, limitations etc., of the aircraft that are the basis of its Type Certificate and which set out the parameters that must be met to be in compliance.

When these details change or need to be corrected, they don't reissue the Type Certificate, they just revise and reissue the data sheet that is linked to the TC by its number, T00015W1.

In your example, Feb 5 is the date of issue of the revised Data Sheet at Rev 4, so there would be three other revisions, plus the original issue (which should have the same date as the TC itself), prior (Page 6 is still at Rev 3, and Rev 4 is Page 1-5, and revision bars show what was changed in Rev 4 on those pages). That's why it's in the document identification block at the top right. It's the issue date of that Data Sheet revision.

The TC approval date is just a reference to the original TC issue in Sept 2019, which doesn't normally change, being the fancy sheet of paper you frame and stick on the wall when you're the engineering VP who led the program.