Samsung Galaxy A-series charges fastest with a charger and cable that both support USB Power Delivery (USB-PD). An open standard supported by Apple, Samsung, Google, and most Android makers; negotiates voltage/current between charger and device.
Using a charger that doesn’t support the device’s preferred fast-charging standard isn’t unsafe — it just falls back to a slower, universally-supported charging rate, typically 5W to 10W over basic USB.
Wireless charging is convenient but generates more heat than a cable, which is why wired charging is still faster for a full top-up.
Look for a charger explicitly labeled with USB Power Delivery (USB-PD) support, paired with a cable rated for the same wattage — a mismatched cable is the most common reason fast charging silently doesn’t kick in.