It wasn’t too long ago that each manufacturer plug made their own charger connectors that were unique to that brand – I still have some of those chargers lying around, don’t ask me why! Inertia?
Then various international bodies got involved, including the EU, and said it was silly, they all have almost the same electrical outputs, let’s standardize the connector. And (almost) everyone has switched to USB-Micro. Then USB-C appeared with its higher current capability and again (almost) everyone switched to USB-C.
As I understand it, a USB-C cable fully compliant with circuitry specifications which can determine the maximum current it can pass to receiving equipment, and if in doubt, resolves to the basic USB standard of , I think, 5V at 500mW. The problem is that there are many USB-C cables that are not entirely standard. However, if you are confident that the charger and cable you are considering are in fact genuine Samsung equipment, then whichever one you choose will not fry your equipment.
Then you have to consider what the manual for your equipment says. If it says the maximum charging current is 3A, a 15W charger will be sufficient (5V x 3A = 15W). If the maximum charging current is 5A, you can purchase a 25W charger.
Shape, size and color don’t matter, it’s the electrical wattage that is important, and in your case I would buy from a reputable dealer so that, as Kelloggs said, if it’s Samsung written on the box, it’s Samsung inside the box!
If you do not have a specific charger with this equipment, it is out of a virtuous desire to reduce electronic waste. If a wall charger charges any piece of equipment, why give yourself a whole new charger just because you’re buying a new phone or whatever?