Your needing a delta connection to get 120/240 voltage with a 208 wild leg.
The only thing that would make a delta have a high leg is bonding the center tap of the opposite winding; not required here. Plus, a standard transformer requires bonding headaches of its own.
If the equipment doesn't require the neutral, two buck-boost transformers can get real close to 240v 3ph as an open delta. The voltages-to-ground will be imbalanced, but that doesn't matter.
If the equipment does require the neutral, three buck-boost transformers can get real close to 240v 3ph as a wye. The voltages-to-ground would be balanced, which matters to such loads.
In either case, buck-boost transformers are more economical here, because each one only has to have the kva capacity to supply the load current at the voltage difference, not the current of the entire load.
In a nutshell, you wire the primary and secondary in series, which creates an auto-transformer, a single winding with a tap near one end. Many units come with dual-voltage primaries and secondaries.
You wire the two primaries in either series or parallel to suit the source voltage, and the secondaries in either series or parallel to suit the desired voltage increase or decrease. The link in post #2 tells you how to select and connect them.
If you apply voltage to the two end terminals, you receive a reduced voltage between the tap and the far end. If you apply voltage to the tap and the far end, you receive a reduced voltage between the two end terminals.