There's been loads of articles and videos over the years, going behind the scenes on transfer deadline day. They all say the same thing, that it really is as frantic and stupid and profligate and often poorly planned as it seems. Here's just a few I found on the first page of a google search.
https://www.youtube.com/watch?v=29z_R6Uk3Bc
https://theathletic.com/4825447/2023...w-summer-2023/
https://www.skysports.com/watch/vide...esdeadline-day
The infamous Odemwingie incident:
https://www.thesun.co.uk/sport/23762...e-day-caulker/
https://www.independent.co.uk/sport/...s-8477964.html
So a fair amount of proof.
Whereas you seem to be basing your entire argument on your friend's son free transfer to Burton. Might I suggest that perhaps not every transfer deal is like this one?
I'm sure players and agents are often in talks with clubs (a number of clubs) a few weeks before most deals are finalised, but what everyone here is disagreeing with is that the deals are 'done' at that point and only kept back because it's "all part of the drama."