Choosing the right PTC Resettable Fuse for a protection circuit
Your approach would work, at the expense of efficiency due to the diode drop on the input.

Here's a discussion on the topic: https://www.edn.com/protecting-against-reverse-polarity-methods-examined-part-1/

This device from Maxim provides overvoltage and reverse protection, with the addition of two FETs. It has no diode drop, so less power loss. More here: https://www.maximintegrated.com/en/products/power/protection-control/protection-ics/MAX4864L.html

Add a PTC of your choice in series and you would have a complete solution.