The app Flow Checker can detect if apps have stopped, b/c the flows involved will ‘break’. Dependable on the check interval, you’ll be informed in a minute. And much more checks with variables and stuff.
Check it out!
I’ve added log cards (f.i. Papertrails app) to every flow. What you can do is use this, or timeline cards, to join all error outputs to one card. Depending on the error, you’ll probably can find out where to look for the culprit.