"struggle by" is correct and usable in written English.
In this context, it means to continue doing something despite difficulties or hardships. For example, "Despite the difficult circumstances, she managed to struggle by."
We can call it waging a struggle by nonmilitary means.
When hostilities again broke out in 1459, Margaret embittered the struggle by outlawing the Yorkist leaders.
Struggle by courageous women and their allies has already had an impact.
Zahawi was never one to struggle by on an MP's £67,000 annual salary.
Stopping it will require a serious struggle by the environmental movement.
Glamorgan are in pole position, but are being made to struggle by Derbyshire in Cardiff.
It comes after a three-year struggle by Connor's family and the #JusticeforLB campaign.
Hundreds more injured, some condemned to a life of struggle by terrible wounds.
This contest for memory is a class struggle by other means.
In prison he was schooled in the Palestinian national struggle by fellow inmates and joined Fatah.
Those who attack our struggle by vilifying me usually say: "Scargill rejected calls for a ballot".
