are phone chargers interchangeable ?
For the most part, yes. Pretty much any charger with a MicroUSB connector will work with your Moto G4.
On the charger question. Are you saying they are interchangeable even if the outputs are different amperes. My moto e charger says 550 mA output and I bought a “supposed” universal charger that says it has 2400 mA output. I guess I’m a bit confused. Wouldn’t a substantially higher output on a charger other than the one that came with the phone, potentially damage the phone?
modern phones will limit what’s coming in no need to worry about over amps