1. Sometimes, you get specific requirements (outputs) from powerful stakeholders or the company's founders. Reverse-engineer them by asking: "how do you measure the success"? And then, "If I do it differently, would that be ok?"
After a few questions, you have your outcomes.
2. If strategy 1 doesn't work, wait one day and say: "We'd like to use OKRs as Google does." Then reverse-engineer the requirements and start the discussion about OKRs.
Define objectives as outcomes. You have your outcomes.
Try it, and let me know if you find this short format useful.