Make sure the connection to the charger is correct. Use a proper Samsung compatible or a branded C type cable/charger. If the issue still persists, contact your nearest Samsung store and get your charging port checked.
I agree to what you said, A13 is amongst the basic models of Samsung phones, and if the usage gets heavy than it is supposed to, it will start to hang a little. It might come with more RAM but it's the processor and the usage that matters. Samsung is...