With fixed size, order does not matter - addition is commutative. With percentage sizing it matters a great deal, because each trade's size depends on the equity the previous ones left behind.
Where order does not matter, it is worth knowing why. Five gains of 10% and five losses of 10% multiply to (1.1 x 0.9)^5 = 0.951 in any sequence, because multiplication commutes too. What order changes is everything that depends on the path: which trades were taken at what size, whether a drawdown limit fired, and whether you were still trading when the good run arrived.
That is where the damage lives. A strategy that hits its 20% drawdown-throttle in the first thirty trades runs the next hundred at half size; the same trades in a different order never trip the throttle and compound at full size. Same edge, same trades, materially different ending balance - and only one of the two paths ends with a trader who still believes in the system.
This is why monte-carlo-reshuffle tests exist: your realised equity curve is one draw from the set of possible orderings, and the drawdown you actually experienced may be far from typical.
Related: monte-carlo-reshuffle, variance-drain, drawdown-throttle, closed-vs-open-equity