Maximum current input of an LM2596 step down converter
You can use it so long as you take no more than 3A out of it. If you're buying one of these LM2596 modules online, taking more than 1.5A out of them tends to cause them to overheat and shut-down.


It looks fine in your application, as it's only running the small logic module.  I'm concerned about the MOSFET. if the LED strip wants several amps the current through it could overheat the solderless breadboard.

In that case run a wire directly from the 12V socket to the MOSFET and another from the MOSFET to the strip and a third from the strip to the socket so that the LED current does not flow through the fragile solderless breadboard.