"widespread of" is not correct English
You should instead use the phrase "widespread" (e.g. "The disease has a widespread impact on public health.") or "widespread among" (e.g. "The problem is widespread among young adults.")
The most widespread of these was tattooing, practiced by both sexes.
The common periwinkle, Littorina littorea, is the largest, most common and widespread of the northern species.
Among the most widespread of these are the dhali, baul, manipuri, and snake dances.
Blue Willow ware was produced by many subsequent factories, perhaps the most widespread of domestic designs.
Globigerina ooze is the most widespread of the oozes and occurs in both the Atlantic and Indian oceans.
It has been the feeling, unquantifiable but widespread, of a growing disaffection among its core voters and activists.
It has become increasingly common as the more widespread of IVF has led to a substantial rise in multiple pregnancies.
Nevertheless, it was perhaps the most widespread of the hashtags that have been, in recent years, the umbrellas for collective conversation and bearing witness about violence and survival.
Modern 911 technology can be broken down into three levels, the most basic and widespread of which tells dispatchers the phone number and address of land-line calls.
Poverty remains widespread, of course, and some may find it hard to cope with the contrast between the smart resorts and what lies outside their walls.
In short, this is a study of friendship — the most widespread of human transactions, far more common than love, but treated by the movies with comparative disdain.
