I am facing the same problem, as soon as users have to login, and you have to make requests in their regard. E.q. if you provide a service for a lot of twitch users then the 120 calls limit is getting problematic rather soon.
An custom rate limit for authenticated requests (e.q. via bearer token would be great), then this limit could be lower and it would make it easier for developers, at the moment you have to provide a worse user experience than necessary, and it is sometimes hard to guess how fast your app will grow in these cases so it is not always feasible to request an rate limit increase beforehand.