Extreme slew rates like 200V/us or 300v/us no use in general but can it be achieved?

[Elvee]

wouldnt that rob the bandwidth?... and microdetails..

If you hate the idea of heavy NFB, there are other ways based on the Tringlotron principle: for example, the Tringlophone can theoretically achieve zero (and even less than zero!) output impedance, without a trace of negative feedback in the OP stage.
UniGaBuf uses the same principle in a different topology

 

[knutn]

Here is an (old) example.....

 

[Bonsai]

Marcel, yes, I think we are in agreement.