11-16V DC voltage stabilization for 13.8V powered ham radio
Setting up parallel switching regulators is hard. They might not run in sync and start supplying each other. Also, you're saying you want 25A. You would need a ton of those regulators to make it work, if it would work at all.

My suggestion is to get some big coils and FETs that can handle currents like 30 - 40A and a buck-boost converter. Alternatively, you could begin with a buck converter and regulate to a like 10V, and then boost up to 13.8V again. Don't expect to find these regulators in a package that will supply, you'll have to add external components. Don't forget that a buck converter needs to handle 25*13.8/10 = 34.5A+ (not accounting effiency) , because the voltage is lower.