The loudness reference zone of streaming platforms shows that all LUFS values above a certain minimum value are "ok". This minimum value represents the reference loudness used for loudness normalization by the respective platform. For some in-depth information on loudness normalization for streaming platforms, check out this blog post.
Loudness & Streaming Platforms
Almost all streaming platforms normalize every track to some reference loudness (e.g. -14 LUFS for Spotify). So while it would be a bad idea to sacrifice dynamics to make a track really, really loud that will be turned down later on anyway, making a track louder than the reference is no problem at all.
Yes, it will be turned down – but so is every other track. Every track is normalized to the same perceived loudness level, meaning that no track is louder than another after normalization.
It’s only important not to fall BELOW the reference loudness of a platform. If a track is too quiet it will be turned up - and that can lead to unwanted limiting. That’s why true:level and smart:limit qualify all loudness values above the reference loudness of a streaming platform as good.
Hint: If you want to, you can turn down the track to a certain reference loudness using the linear output gain of smart:limit. But please note that the end result on the platform will not change, since the platforms will also simply linearly turn down the gain. ;)
Loudness Standards suggest an actual target loudness (not only a minimum reference loudness). As a consequence, all loudness values above or below the loudness target of a loudness standard are potentially a problem and true:level and smart:limit will show a respective hint.