They do have a clean sheet design: e-TNGA. The Toyota bZ4X and the Subaru Soltarra are both based on the design, along with the bZ3 and the upcoming Lexus RZ.
e-TNGA just appears to be an e- added to commonize with the TNGA gasoline architecture.
> Now Terashi’s group is considering whether to drop the three-year-old e-TNGA architecture, created by modifying a gasoline car platform, in favor of a dedicated EV platform, people with knowledge of that work have said.