Related to the other comment about HR having their own goals...
HR may want to get rid of that engineering manager anyway, so they can be replaced with someone that improves their demographics quotas, I mean targets.
I have actually seen such targets in some OKRs for one or more HR teams, somewhere.
I've never heard of a highly effective engineering manager being replaced to meet a demographic target. I'd be surprised if this has ever happened, much less being an actual industry problem. I could see them replacing an engineering manager, for reasons unrelated to the target, and replacing them with someone that helps move them toward their target -- but those are drastically different things.
HR may want to get rid of that engineering manager anyway, so they can be replaced with someone that improves their demographics quotas, I mean targets.
I have actually seen such targets in some OKRs for one or more HR teams, somewhere.