I like DORA metrics as a guideline (Deployment frequency, lead time for changes, change failure rate, time to restore) which aren't perfect but are fairly straight forward to understand and measure. I might look at number of production touches(manual interventions in the delivery pipeline), story points estimated, story points delivered, number of pages, number of bugs created/closed/closed w/ change, number of errors/exceptions. It's possible to hide technical debt here but it eventually start to manifest in one of the stability metrics (bugs, exception, production touches, etc) or a drop in velocity .

Though is more about engineering delivery of the product roadmap. I do like the 'bets' framework in the OP to figuring out whether the product roadmap actually results in meeting the desired goals for the organization (growth, profits, whatever) but these should be measured as different things.