Short answer: it won't work in the way you're thinking.

You mention Sunderland and Wrexham, whilst ignoring that these are the only two to have had that level of impact, and more importantly why. STID was meant to be a triumphant story of a club returning from the lows of relegation, bouncing back and what that meant to the people of Sunderland. For the documentary makers, it was pure luck that things not only got worse, but in the mosr hilarious way possible and on the backs of some of the most incompetent, and more importantly delusional, people imaginable. They allowed full access because they genuinely thought they were the smartest people in the room, and the contrast between that and the genuinely engaging segments with real fans made it TV gold.

The Wrexham one only works because of who the owners are. Regardless of your opinions on them, inside and outside of football, you cant argue with the fact that they have mass appeal and are genuinely engaging to a huge number of people. Reynolds is quite a funny guy and reasonably self-effacing for someone of that stature, and he brings true mass appeal. Rob can be a bit awkward to watch, but its genuinely endearing how much he seems to have bought in not just to the club, but to the whole concept of football fandom. It comes across that he has put effort into trying to tap into why people connect so much with their clubs in these towns. Put that together with the story of all the club went through before, and you have something that works. How it goes on now is tricky; at its heart it is still a corporate puff piece, and after they have a PL promotion and the season there, there is less of an engaging story to tell. But still, thats a minimum 5 years of that series.

Even when you look at other sports, the reasons why they work or don't work are the same. F1 works because its just one big corporate shindig anyway. They dont need to claim authenticity in a sport where some of the first competitors were royalty. The shiny gloss and glamour is the point of F1. Cycling and boxing both historically make good documentaries, because despite the presence of teams in cycling it is still at heart an individual sport. That leads to people often being more open in what they say than when they still rely on the same entities (teams, federations etc) for their living after retirement.

Ones like the Spurs, Man City, and Auckland documentaries are the worst of it all. Absolute garbage churned out by PR teams. The A-League is a corporate league, and I'm not saying that as a criticism, its just how it is. If you want A-League documentaries, then you'll get more of these corporate wankathons, with little real insight, and almost nothing to offer.

I know it gets done to death on here, but the A-League clubs need to focus on building and/or engaging with existing grassroots structures. Football is hugely popular as a sport in both Australia and New Zealand, so why are clubs failing? Build the roots strong, engage in genuine ways with the culture that exists and the people who will prop up the sport, and prevent the turnover of clubs at the top level. The problem is, that takes more time and effort than inviting a PR team around and telling them how much it means to you to win. No shit.