The SoC% your computer shows you
is on the scale from 0% - 100% that the engineers defined, not based on the data sheet specs from the cell maker.
So maybe not 20% - 80% but certainly shooting for good battery longevity rather than maximizing every mAh scrap of capacity utilization.
That said, keeping your cycling around the 50% mark will give you many times more cycling lifespan
than going all the way from top to bottom.
Staying between 40% and 60% might last for a decade.
But too much trouble, replacing the battery is cheap and easy.