Calculate power supply for step down modules
I'd go for 220V AC to 24V dc because this type of power supply are likely to be more common and give you more "buy" options. Another reason is this; converting 24V to 5V using a switching regulator will give you more options on the switcher chip because there are fewer switchers capable of converting 32V to 5V than 24V to 5V. Almost without any uncertainty at all, a buck switching regulator that works at 32V will always work at 24V but not vice versa.

Even if you were to choose isolating modules for the final 5V conversion (using a flyback topology to provide isolation) 24V is a standard input voltage.