I asked a similar question a while back, about metrics for testers as I was trying to come up with SMART goals.
While my company has fully embraced goal setting, I’ve found it really hard to do as an individual, especially as you allude to, coming up with something measurable, and especially something quantitative.
The more I thought about my goals, it became obvious that all the things I’m being measured on as an employee are more reflective of my team, and especially if you’re doing agile/embedded, you’re not necessarily specialized and you’re ideally doing what the team needs, which may or may not align with a goal you came up with months ago.
My manager agreed, so we mainly do pro forma usage of the goal tracking system. If the team is struggling, we try to figure it out as a team, and try to improve in that regard mainly via retros. That’s not to say everything is rainbows and unicorns (we had a prod incident last week that’s definitely got our morale down, and trying to sort out some of the aftermath is going to be a slog), but really, we’re learning from it and trying to make our product and processes better.