[nitwit005]

But, it tends to be difficult to find any metric that's meaningful.

For example, increased test flakiness can be a positive sign. I know that seems unlikely, but if you see some spike in flakey tests, it's often a side effect of people adding end to end tests, because some issue made it to production.

At my current job they monitor how long PRs are open, and it appears to mostly be a measure of repository age. Old repositories have more PRs sitting around.

What you really want to measure is "how good is the product?", or "are we delivering quickly relative to the difficulty of what's asked?" and those turns out to be extremely expensive to measure, so people use metrics that don't work well instead.