Fuel Smell In Cabin When Idling/Stopped

Hi folks, I've been researching everywhere and just wanted to see if anyone had any additional suggestions.

Symptoms:
Fuel (gasoline) smell only inside the cabin when the ICE is running, with HVAC turned on, and car is parked, stopped, or at very low speeds. Smell reduces when I flip the HVAC to recirculate. Issue persists through all weather conditions, all fuel levels, all lengths of time, all engine temp states.

Investigation:
I can find no fuel smell at all anywhere outside the cabin, including anywhere in the engine bay, or anywhere underneath the car.
No check engine codes, no fuel smell in the exhaust, no reduction in fuel economy, no visible fuel leaks anywhere I could see. Fuel cap is tight, no smell there either.

Per other posts I found, I plan to make sure my spark plugs are torqued correctly, and perhaps replace my fuel injector o-rings.

Several mechanic friends have suggested it's probably something with the EVAP system, perhaps even the purge valve, which I believe is nearby the HVAC intake.

Any suggestions or advice I'm happy to take. Found plenty of other people posting about gas smell issues, but usually it's dependent on fuel level, temperature, and/or can be smelled outside the car.

Thanks in advance.