I do not believe that the ‘market’ is ‘red hot’ any more, maybe in the lowest price range, because people are being scared into buying and that that they are ‘going to miss out’

A MLS listing is instant when it gets listed.
There is no (*VALID*) reason to list it if the agent has a solid offer, unless they want back-ups. There is no time lag that makes it an ‘unofficial’ listing.

It is possible to have an offer the 1st day though.

You are referring to 3rd party websites that sometimes use outdated information. They automatically track MLS but can be delayed.
There are other sites that do not track MLS, an agent has to list the property there manually.
If they do not do it at the same time as they upload MLS, it gets distorted. Another problem is that the manual sites need to have a manual update when an offer is accepted or it still shows as ‘active’ but it’s not.

A lot of the statistical info is inaccurate but quoted like it is from the bible. (You are also dealing with some sales-people that have no ethics)