Upgrade to Sequoia or Tahoe for external display?

Duet works, thank you. I’d forgotten I’d bought it a few years back.

The config I’ve settled on is as follows:

  1. Duet to extend my main MacBook display to my iPhone via a cable
  2. Amphetamine on MacBook to stop the (iPhone) display turning off when I close the MacBook lid
  3. GP Selector extension to provide an iPhone-size screen optimised display of songs and song parts
  4. Hardware buttons on Arturia Keylab mapped to Song and Song Part (Previous & Next).