The phrase "overwhelmingly focused" is correct and usable in written English.
For example, you could use this phrase to describe someone who is single-mindedly devoted to a certain task or project, such as a student who is "overwhelmingly focused on achieving a high grade."
First, the risks of Ebola spreading are overwhelmingly focused in Africa itself.
StanChart is overwhelmingly focused on Asia and Africa; only 3% of its staff are in Britain.
The ICC has overwhelmingly focused its investigations on allegations against Africans.
The literature has overwhelmingly focused on incremental adjustments in institutions and resource management practices as possible solutions.
But this new indicator is overwhelmingly focused on the recording rather than the doing – process rather than outcomes again.
The media, for example, overwhelmingly focused their attention on the accused over the experience of his accuser.
Although the Black Lives Matter hashtag was created by three black women, the movement has overwhelmingly focussed on black male deaths.
Aid workers protested against the blocking of humanitarian convoys, bore witness to atrocities and provided the media with a steady stream of stories, which overwhelmingly focussed on the misdeeds of the stronger party.
Instead of forcing people to overwhelmingly focus their time and attention on a single screen, broadcasters, sports teams and "appreneurs" increasingly seek to monetize divided attention spans by promoting multidevice engagement.
Over and over again I've found that people overwhelmingly focus on a) the fear of being hungry and b) value for money, which both lead to choosing large portions.
But US policy towards the region is now overwhelmingly focussed through a single lens - the effort to contain Iran.
