You should be watching the generation capacity rather than efficiency.

My roof happens to be incredibly well aligned for solar, and most months I generate more energy than I use. About 1.2 MwH per month. The fact that the panels are “only” maybe 19% efficient doesn’t really factor into my reality. The factors that matter are system output, cost, and my usage.

Efficiency helps on the power output per unit time, but better to focus on the end goal rather than the contributing factors. Depending on your location and house design, you might be good to go already, or even a hypothetical 30% efficient system would fail to get you everything you need.