Something like an upgrade from that source to the current-based
Questyle M15 would undoubtedly bring your s12 pro to maximum, especially with the balanced 4.4mm cable connection. And, using what's left of your budget with a bit of a stretch, you can add the highly-resolving over-ears
HIFIMAN Sundara to your fleet. If you can't stretch your budget that far, then the excellent alternative would be the
HIFIMAN HE400se. You'll want a balanced cable for each of these ones, too. This collection can be considered as complete for the vast majority of music lovers.