you can do both: report a number that shows how often your service as a whole is degraded, with a breakdown for individual components

example (not sponsored, i barely use codex and today's the first time i've ever had to look at this page; i don't know how much they're fudging the individual numbers or not reporting minor incidents):

https://status.openai.com/

most people who use chatgpt don't use all of the components under the "ChatGPT" heading. for codex, i don't use the vscode extension or codex web. etc