Maybe, but they have used many manhours on the GR Yaris, testing it. Not specifically for rally, but instead of starting from scratch.

Think of the PR the car will get. You can actually with a full rally-kit by GR, take it into the forrest!
Of course not as a Rally3, but more a cupcar.

But Toyota is a big organisation, they should be able to make a Rally3 car quite fast, and have it ready for sale in November 2021.