The phrase "a foothold of" is correct and usable in written English.
It can be used to describe a position of advantage or a secure place from which further progress can be made, often in a metaphorical sense.
Example: "The company established a foothold of influence in the market, allowing it to expand its operations."
Alternatives: "a stronghold in" or "a base of".
It's an area that's still on the turn, and one backstreet basement is a foothold of the gentrifying incomers.
"There is concern that this circumstance could allow a foothold of resistance to form among refugees and breakaway soldiers.
The administration reckons other countries will be beating down the door to "help out" afterwards as a way to gain a foothold of influence.
While Mr. Balazs and Mr. Platt labored to open the Mercer hotel — Chateau Marmont East — in the early '90s, Mr. McDonald was looking for a foothold of his own.
Finding a foothold of courage from somewhere, among the dozens of interviews and articles that I wrote in the ensuing few years were a few that talked about sexual abuse and its legacy, and the messages of support and gratitude I received as a result of these ran into the thousands.
The purchase is likely aimed at giving Foxconn a foothold of its own in the peripherals and networked devices market.
Tiny cracks might have crazed the rock, providing a foothold for fibers of quartz and crocidolite.
As a result, it has never quite gained enough of a foothold to be taken seriously as part of UK musical culture.
By 1991, Mr. Rosen had established enough of a foothold to start a real estate business, RFR Holding, with Mr. Fuchs.
Intel in particular is trying to get a foothold inside of retail where they hope to promote their Internet of Things strategy.
The main assault successfully pushed onto the ridge, and the 56th Division advanced about 1 mi past Croce, before digging in on the evening of the 13th; that night, the 4th Indian Division gained a foothold south of Gemmano.
