Why did you replace the thermostat with one that opens at a higher temperature than the OEM thermostat?
I suggest installing the correct thermostat, going through the drive cycle, and having the car retested at some place other than a chain shop. You keep going back to the place that failed your car. Why are you doing that?
Take the car somewhere else. I suggest an independent mechanic, not another chain shop.
I’m not familiar with the CT emissions testing procedure, but it seems to be a profit generator for chain shops that say “Failed,” but don’t tell you why.
How will you ever know what to “fix” if they don’t tell you why it failed?