Does this make sense?

I can’t lose a 0.5% risk trade then go to 0.25% on the next one thinking that’s a good idea because in order to be profitable long term the sum of my small amount of winners must be greater than the sum of my even more numerous losses.

Also my winning trades would have to move much further if I risk less than 0.5% to be profitable.

E.G.
Audusd trade with 0.25% risk ($10) is a winner and after managing the trade for 45 mins I eventually get stopped out in profit and win $15 (0.3%). Its such a low win that it doesn’t wipe out the $25 loser (0.5%) I had from the previous day so this risk management strategy applied overtime with my low win rate is ultimately going to result in a blown up account.

Perfectly reasonable, and as you’ve probably already thought, it would make more sense if anything to increase your risk after a loss instead of decreasing, or decreasing risk after a win.
In general, there aren’t very many instances where decreasing risk after losses should be used, at least in my experience.

As for me, it is better to use the same risk in each trade and to increase it only once in a quater, or each 6 month, for example.