parallel configuration of diode
If the diodes attempt to share  the same current so that neither  carries the full load, which could exceed its own thermal-related max current, then they  must have an internal resistance that is well-matched rather than >+/-50% worst case tolerance from different batches and also both have excellent thermal conduction to some heat sink. Otherwise if this internal resistance is well matched so that the rise in temperature of each may result in a 60’C rise equally such that the diode Vf drops x.x mV/mW of heat so that they still share current equally.

The requirement here is that the Vf drop with rising temperature) has both a good thermal conduction and good Rs equivalent match in values (Vf@1A-Vf@1mA)/1A = Rs. ( or as I prefer to call it ESR or “internal bulk resistance”).  As long the voltage rise due to current is greater than the voltage drop due to temperature rise and mismatched tolerances, it will be thermally stable.