One arm, low pulley, sweeping up across your body for the inner chest.
Keep the elbow angle fixed and drive with the chest, finish high to nail the upper inner pec.
Sweeping a handle from a low pulley up and across to the opposite shoulder loads the chest on a low-to-high arc, the line that puts the upper and inner pec fibres under the most direct tension. The front delt assists as the arm rises, but the fixed elbow bend keeps this a fly, not a press. It earns its place as the finishing touch for the upper chest, one side at a time, where flat pressing leaves the fibres near the collarbone undercooked.
The upward arc lines the resistance up with the upper chest fibres that run toward your collarbone. High-to-low crossovers bias the lower chest, so the two are siblings, not substitutes.
Because the moment the weight is too heavy, your elbow bends and it becomes a sloppy press. Pick a load you can sweep on a fixed arc with a hard squeeze at the top of every rep.
Hand up and across your body, roughly in line with the opposite shoulder. Finishing high is what keeps tension on the upper inner chest instead of dumping it at your midline.
