2011 Jeep Grand Cherokee P2181 and P0113 Codes: Overheating and Heater Not Blowing Hot Air

I'm experiencing two diagnostic trouble codes on my 2011 Jeep Grand Cherokee: P2181 and P0113. The vehicle is overheating, and the heater isn't blowing hot air. I took it to O'Reilly's for diagnostics, and these were the only codes returned. I'm trying to determine whether the issue lies with the thermostat or the Intake Air Temperature Sensor (IATS). While reading online forums, I suspect the IATS is unlikely to be the root cause given its symptoms, but I don't want to spend a significant amount on a replacement if it's simply a faulty thermostat. The mechanic at O'Reilly's estimated a repair cost of $500—however, I haven't had these issues before the vehicle left their shop. Any second opinions or troubleshooting advice would be greatly appreciated! Thanks in advance.