I just checked the factory service manual and to replace the CVTF coolant thermostat, it is not required to remove the intake manifold, nor is it required to replace the EGR valve (gasket), but the engine does need to be lifted to replace the EGR cooler. Is it possible that you're having leaks from both coolers?

There's a list of recommended subaru specialty shops if you want to get a second opinion, if you live near one of them:

Other: - List of Recommended Independent Subaru Repair Shops

Updated September 16, 2023 Totally stealing this from ForesterBill on SF.org... Looking to start a list of independent Subaru-focused repair shops that forum members recommend. The shop must primarily specialize on Subarus and not just generalize on multiple brands, although it does not have...

www.subaruoutback.org

 

I'm wondering about the coolant hose(s) on the oil cooler. You didn't list hoses and a hose is more likely to leak than the cooler housing.

The oil cooler labor is 1.3 hours. So you would multiply that times whatever the shop labor rate is. Replacing the CVT thermostat is only an extra 10 minutes if you're changing the cooler because the coolant hose going to the cooler is removed from the thermostat housing to get the cooler out. After that it's two bolts that hold the thermostat housing to the crossover pipe.

The intake boot, which is the tubing that runs from the air filter housing to the throttle body is the only thing taken off as far as air intake is concerned. EGR is not in the way of any of the work.

The oil cooler retails for about $140. The thermostat is about $27 - $30. You're two coolant hoses are about $22 a piece.

So I'd say even if the cooler was leaking, he's got it overpriced by about $350 to $400.

Maybe it's one of those shops who overprices things to run you off because they're scared to do it. Maybe they're saying the cooler leaks to get a higher cost repair out of you. I'd be looking at the hoses. Because if the cooler is actually leaking it's either the housing expanded which makes it a high likelihood that there will be coolant in the CVT fluid, or CVT fluid in your radiator, or it might just be cracked at the point where the hose nipple is attached to the surface of the cooler.

My experience has been a leaking hose.

Edit:. I enlarged your mechanics picture and that looks like the CVT thermostat gasket is leaking. So that takes the oil cooler out of the equation all together. So that's about an hour labor and the thermostat. The thermostat comes with its gasket.

 

Thanks so much.
I am in western Colorado in a rural area.