If I focus exclusively on input, won’t I struggle to speak when I finally need to?

Actually, the opposite is true. According to the “Input Hypothesis,” speaking is the result of acquisition, not the cause of it. By bombarding your brain with high-quality, comprehensible input, you are building the “mental library” of patterns you need. When you have enough input stored, speaking emerges naturally and with far more accuracy than if you had forced it from day one.