Ultimately, the bigger context is what those errors, + and - plus bring in terms of runs allowed. Zubinsum had a good thread on those values several years ago. I’m on my phone now, so finding it may be a challenge currently, but in short, the value of a +/- play is usually 1 base (it can be more, but in aggregate, it’s essentially a 1 base event). Errors vary more position to position. For OF, errors are usually 2 base events. For IF, usually 1 base events. All aggregated together the run value of a +/- play is around (from memory so might be off) 0.30-0.35 runs. Whereas an error has a run value of around 0.65-0.70 runs.
obviously these values will be heavily team dependent. If your team makes all of its errors in the OF, that’s going to equate to more runs allowed than your opponent if they made the same number of errors, but all in the IF. Likewise, you can’t just aggregate errors and +/- plays together for a detailed value as the breakdown of what position they come from changes that run value.
similarly, your catchers CS/SBA rate AND the number of attempts is valuable in deterring the defensive run value of your catcher. You could have two catchers with similar CS rates, but the one that reduced
SBA could be more or les valuable depending on what that rate is (from memory each SB is 0.18 runs and each CS is -0.27 runs).
In general, I do what ryno does when evaluating my defense and do a simple (+ plays) minus (errors plus - plays) to get a net defense event and multiply by around 0.42 runs. When it’s close I’ll multiply errors by 0.65 and the net +/- plays by .35 and and subtract the error value from the +/- play value.
I don’t usually bother to get more detailed than that even though it is more accurate.
I always calculate out catchers run values to the exact detailed value.