So ideally you have some kind of monitoring that reports/shows how many services are alive (and where they live in a cluster), how many errors they generate etc. Then based on some thresholds you can take them out of circulation and let them cool down. If certain kinds of errors occurs, or at a certain frequency, the system can notify a site reliability engineer (or equivalent) to check it out. Then they can decide if it should be permanently removed and to log an internal support ticket and so forth for the developers or product teams.

Production issues are a part of life. You need to have some visibility on issues and their severity. Every company and tech stack is different, also depending on their SLA's and uptime promises.

Ads not rendering in an app might be less severe than a pump failure at a fuel station, so they have different kinds of monitoring and and reaction times to faults. Obviously things like hospitals, banks, airlines/aircraft manufacturers have way different requirements and infrastructure from say a system that manages all school libraries for a state/province.

There are too many products and approaches to mention here if you were looking for a list of those. I have one or two favorite approaches and a handful of tools for this kind of stuff, half of which is homemade, so not something you can google. But you can google it and see a few different approaches. "microservices monitoring java" or "microservices monitoring best practice" or something along those lines will get you on a path. Try to find 5 different approaches and reflect what each one is missing or how they may help you, and then ponder what would you like to see from a reporting system with hundreds/thousands of services.

And then obviously the the best lessons will come from production itself.

Good luck!