augmented & suspende

It’s still difficult to answer if I’m honest, not something I’d normally care to worry about. Sus 4 chords are often used as decoration to lead in to a major chord. Most of the time we wouldn’t care much about the 4th scale note being in key or not. If you want the chord to replace another chord then the key might matter. For instance, in the key of C you could play a  CSus 2 or CSus  4 instead of C major, you’d still be using notes from C major. Over the F chord you could play Sus 2 but F Sus 4 would put a Bb note in, which is outside the key of C major … doesn’t necessarily mean it will sound bad though. Minor chords, technically you could play them as Sus chord but they would loose their minor flavour because you would no longer have a b3 in the chord. It can all be rather complicated and you are really better off just trying and listening, if you like it then that’s OK.
If you are talking about how a Jazz player might think about Sus chords then it can become a very different and complicated conversation. I’m not much of a Jazzer so you would need to study jazz. They probably wouldn’t be thinking about Sus chords in isolation or necessarily strictly related to the key. Jazz goes deep into harmony and will often use Sus chords, often altered and combined with certain modes. This gets very in depth, probably goes beyond my own understanding because I don’t study a lot of jazz.
In the rock / pop world it’s really a matter of playing something and liking it or not. If jazz is your thing then you need to study jazz harmony and brace yourself for a heavy ride. 🙂