Ammonia buildup means a wash routine issue. Stripping should only need doing, if something in your diaper needs killing, most commonly, yeast, unless you know you have ammonia. Stripping can also be done when buying used. Use enough detergent, even in your prewash. Usually about half the amount required for a heavily soiled load, as the prewash, and a bit more than required for a heavily soiled load, in the main wash. More if it's an eco friendly actual detergent, or unless something has changed, a free and clear. If a detergent says, "just use less in an HE washer," it's not HE safe, even if it says so.