R510s are already end of life. I would suggest R650 which is 11AX standard with 4X4 radio chains. For more info please refer the Data sheet for better comparison.
These are indoor APs, unless the users sit in such harsh environment without Airconditioned room, it shouldn't impact the AP performance. Though the max advertised temperature is 40C, we do consider a factor of safety and allowed to perform better with few degrees beyond that.