Glad to hear you are making reasonable progress.
I finished reading Brooks book for the second time today, and spent some time on the final chapter about his favoured set-ups.
I have been useless at discretionary day trading before, and have moved to an automated system which has been passably successful, though it struggled a bit with volatility during Trump's last year (I trade the Dow Jones).
The problem I have with day trading is that I tend to trade in the direction that the market appears to be moving at that instant. I think this may be what many beginners do, indeed what most retail traders do, but I find it is problematic.
The major thing I have got from Brooks is to trade with the trend. Indeed he says many times in his book not to trade counter-trend until you are making steady profits on with-trend trades first, as finding good counter-trend set ups is much harder. By trading with the trend, he doesn't mean with the trend of the last few seconds or even minutes, but with the underlying trend (if there is one) which might last anything from 5 or 10 minutes, to a few hours when you are day trading.
This often means trading pullbacks or sudden reversals in the opposite direction to how I would have traded them before, and it's mentally hard, because the market appears at that moment to be moving against your adopted position, even though you are trading with the underlying trend. However a little experience has shown that the results are much better. The last couple of days on the Dow have had many opportunities for classic Brooks trades.
Having read Brooks book twice now, I think it has some excellent content, though it is poorly structured and hard to follow. He explains the nuts and bolts of day trading in a way I have not seen before, and which makes a lot of sense to me. Talk of bull and bear traps, stops being run by the market, and being trapped in trades makes a lot of sense to me as a chess player; you are competing against smart people here, and only some of them can be successful. If you trade the same way as most other day traders, by definition you will not be successful, as most day traders are not successful. It is a very hard skill to pull off.
One final point; I would be cautious about thinking that trading with a demo account is the same as trading with hard cash. I have tried both, and for me trading with real money (though only a small amount of it) is very different. I am conscious that with a demo account, I am much less risk averse than I am with real money. It may be different for other people, but for me it makes a difference.
Still, as you say, for proving a concept may work, it is perfectly reasonable. It just may be harder when you come to put money on the table.