Asus is geared to release a compact premium phone in the form of the Zenfone 8 Mini. That phone could be closer to release than expected, as it has now been spotted on the TUV certification website, with information on charging specifications.
https://www.notebookcheck.net/The-Asus-Zenfone-8-Mini-draws-closer-to-launch-as-it-appears-on-certification-website.531312.0.html
Knowing Asus, this mini device will probably target 500-600$ dollar segment
5.9"? That is hardly mini to me. Even the 5.5" Google Pixel 3 looks mini to me.