What do the different dates in a TCDS mean? I have been trying to interpret Type Certificate Data Sheets and am coming up short on how to understand some of the dates listed. For example, here is the TCDS for the new Citation Longitude:

How is one to interpret these dates? Did the type certificate get issued in 2020 or 2019? The Textron Aviation website has a news release in September that claims certification occurred in 2019; so is the 2020 date specific to the TCDS being released, even though FAA approval occurred in 2019?
Also, how does this related to the Revision numbers? Does the 2020 date refer to Revision 4 and the 2019 date refer to a different revision? I can't seem to find the earlier revisions on the FAA website either, so I am not sure whether they even exist as official/released FAA documents.
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.