Loads of GPUs with Vulkan support use TBDR. The Adreno GPU in the Steam Frame's SnapDragon SoC, for one.

There is also a Vulkan driver for the M1/M2 GPU already, used in Asahi Linux. There's nothing special about Apple's GPU that makes writing a Vulkan driver for it especially hard. Apple chooses to provide a Metal driver only for its own reasons, but they're not really technical.