IMO I've heard good things about all three.

In terms of long term reliability, I'd probably place the Corolla at the top, then the Camry, and then the Yaris.  For the Camry, the 4-cylinder models are probably more reliable (and the non-AWD models).  I've heard people with Yaris's going 150k with almost no problems so depending on your budget, they can all be good cars.  Part of vehicle life is also dependent on how you drive and the maintenance.  If you don't take care of a car, even if it's a Corolla or Civic, you won't get a very good life out of the vehicle or will have a lot of expensive repairs.

If you're concerned about reliability, also consider the Civic.  That would be my second choice beyind the Corolla and Camry (or I would maybe say the Civic is about on the same level as the CAmry in terms of reliability).

Even Scotty will tell you the Corolla (depending on which year you buy) is a very reliable car.  They're obviously not luxury cars, and in my case, road noise was too much so I went with a Camry, but really if you get a Corolla or Camry and take care of it, it can last you a long time.

Basically, if you're looking for cheap, Yaris is the way to go, but I would really think twice about it first.  They are basically no-frills car so you're literally getting basic transportation for around $15k.

In my opinion, the Corolla will outlast the other two. But the Camry is a very close second. The 2020 Yaris is not a Toyota, it’s a rebadged Mazda 2. 

The most reliable and the most expensive: Camry

At least reliable and the cheapest: Yaris

For the size I would say the Camry, I have one 2019 LE.  but if you want a vehicle that's a little bigger than the corolla, look at a Honda Civic, LX or Sport with the 2.0 NA Engine.