"gain increasing control" is a correct and usable phrase in written English.
You can use it when talking about a situation or person gaining more control. For example, "The manager is trying to gain increasing control over the company's finances."
Abundant evidence shows that al-Qaeda in the Maghreb (AQIM) have exploited the rise of Boko Haram to gain increasing control of the Nigerian militant movement.
As we are today dependent on the ability to control our food resources and buffer our risk of food shortages through large-scale food production, harvesting, storage, and distribution, along with the use of refrigeration and chemical preservatives, so too, albeit in a different way, did our hominin ancestors begin to gain increasing control over their food resources.
Russian and US airstrikes against Saudi-backed Islamist rebels have allowed Syrian and Kurdish forces to gain increasing control of much of Syria's borders, making it more difficult for Uighurs to find their way to Syria.
Additionally, counselees who did not receive an indication for DNA testing for themselves did not gain increased control over decisions.
As the Dutch colonialists gained increasing control over the islands, they set up schools patterned after those in Holland, primarily for European and Eurasian pupils.
With global demand rising, particularly in China, OPEC has gained increasing control over supply.
Business leaders and free market economic principles have gained increasing control over education, particularly higher education.
She is gaining increasing control over the large muscles of her body and enjoying activity for its own sake.
In 1911, the owners of the Arms Park, the Marquess of Bute's family, confirmed Wales' tenure and the 1920s and 1930s, Wales gradually gained increasing control.
We propose that over the course of species divergence, humans gained increased control of both the vocal and gestural modalities, and therefore not only achieved unprecedented vocal flexibility, but became more adept at manual tasks such as tool-construction and use.
While it is perfectly normal for your child to have a head lag at one month old, by four months, typically developing gain increased head control and be able to hold up their head properly.[12].[12]
