OKRs help us build prudent, evidence-based decision making into the way we plan our work - but won't give you predictability or consistency.
Jeff Gothelf talks about the best approach to leveraging Objective Key Results (OKRs) while planning work and their limitation when not used probably citing that, teams may face unpredictability if they measure outcomes with OKRs rather than outputs. He suggests that OKRs come in handy when the product backlog is reduced and executed in short cycles. He defines this as "Agility" and notes that it is the organizational ability to change course based on newly discovered backlog items thus ensuring it deploys people and resources in the most viable direction.