API Observability: How to Make It Reliable and Fast

i'm curious so what if you've got an API which is used by different user groups. Would you attempt to differentiate between different kinds of users who are consuming this at the API or would you just say let's just aim it for the users who have the highest need and just make sure it's always that they're good? i'm guessing with APIs where I've seen APIs who are used by many many many different you know consumers for total different reasons  It's important to understand which request is for who and you want to know which are the one like if there's if you have many errors and maybe that's okay but for a certain customer that's not okay and you need to