Advice on coolant leak in 2017 Prius (Canada)

In Canada here. We have a 2017 Prius and have apparently been struck by the coolant leak issue. The engine temp light came on briefly, then went off. When I got home I checked the coolant and it was very low, near the bottom of the tank. I refilled it and within two minutes or less (with the car off) it had gone back down to near the bottom. I'm guessing it's the common heat exchanger issue, but nothing's been verified yet.

The car has about 123,000 km on it. I'm not sure what the warranty situation is for this issue in Canada. Does anyone know?

Wondering what people recommend for dealing with it. Is it worth taking it to the dealer (who charges $150/hr just to diagnose)? Can a non-dealer mechanic deal with the issue? Is it worth replacing the part or better just to do a bypass?

Thanks for any advice!