Light switch for multiple fixtures feels warm after a while
Unlikely that the switch isn't heavy duty enough. But the contacts in the switch and/or the connections to the wires may have problems. I suggest replacing the switch just in case it is having internal problems. When you do that, check the wires for any evidence of arcing. If the wires are not in good shape, cut off the end and strip a new section to attach to the screw terminals on the new switch. Obviously turn off the circuit at the breaker before doing any of this.