"key bottleneck" is a correct and usable phrase in written English.
You can use it to describe a particular difficulty or hindrance: for example, "The lack of trained personnel is a key bottleneck in the efficient functioning of this organization."
Loh's achievement, he says, helped to address a key bottleneck.
Slow progress in scaling up finance has been a key bottleneck in negotiating a global climate treaty.
Here, we identified a key bottleneck in BCFA production: incomplete lipoylation of 2-oxoacid dehydrogenases.
A key bottleneck in the production of pharmaceuticals is in the formation of crystals from solution.
Functional verification has become the key bottleneck that delays time-to-market during the embedded system design process.
A key bottleneck in the production of pharmaceuticals and many other products is the formation of crystals from solution.
Prepare reports on the performance of HEP connectivity, including, where possible, the identification of any key bottlenecks or problem areas.
The key bottlenecks in the path from target gene to three-dimensional protein structure determination are defined.
Smart, connected products have allowed Joy to offer Smart Services, such as "lighting up the mine" (exposing the key bottlenecks affecting overall mine performance and productivity) and systematically reducing bottlenecks to increase material flow.
Data compiled from full-scale facilities and the peer-reviewed literature revealed several key bottlenecks hindering full-scale implementation of co-digestion.
Low Coulombic efficiency and fast capacity fading are still the key bottlenecks for practical applications of Mg2Si as an anode material for Li-ion batteries.
