"become challenging" is a correct usage in written English and can be used in a variety of contexts.
For example, "Managing the team's workload has become challenging in the current climate."
Obtaining the drugs needed for a lethal injection has become challenging in many states.
Even something as simple as getting gas will become challenging in the rainy season.
Mental and physical health become challenging to manage in confinement scenarios.
However, with recent trend in the usage of electric buses, cost optimal operation can become challenging.
Funds are growing so fast it has become challenging for them to find suitable investments, Mr. Robinson said.
However, the evidence has become fragmented and it has become challenging to grasp the information included in it.
Conservation of horseshoe crabs worldwide has become challenging as the number of horseshoe crabs were decreased due to human activities.
However, when a numerical model is: i) computationally expensive, ii) high-dimensional, and iii) complex, these tasks become challenging.
Edward A. Gilhuly, managing director in Europe for the big American buyout firm Kohlberg Kravis Roberts, agrees, though he acknowledges that the environment has become challenging.
When a large graph contains billions of edges that cannot reside entirely in a computer's main memory, computing and maximizing H-group closeness centrality both become challenging.
Surgical treatment of the thoracic aorta may become challenging when a rapid switch from left heart bypass (LHB) to cardiopulmonary bypass (CPB) is required.
