Is normal DC-DC fine? It gets ~22-25V on input and produces 5V on output and is rated at 5A. That's the way i use it and i had all kinds of problems in the project but not RPi power problems.
Like a switching regulator? That would be fine, a linear regulator though definitely not from those kind of voltages! Such a huge voltage drop would make a lot of waste heat.
What kind of issues are you talking about?
Oh well, it's a drone interceptor. It was never meant to be easy.
If by chance the supply is a transformer and its secondary has a center tap, you could use a center-tapped full wave rectifier (two diodes) which will yield a reduced voltage compared to a traditional full wave bridge across the entire secondary.