I would like to use sensorless homing with the Duet2 Maestro. So far, sensorless homing is not implemented for the TMC22xx, because the TMC22xx lack Stallguard [TMC22xx=TMC2208|TMC2224, not including the newish TMC2209 though]. However, this doesn't mean that sensorless homing cannot be done without Stallguard. I did a not so quick test that was quite promising. In essence, instead of checking the Stallguard status during homing, one has to check PWM_SCALE_SUM against some threshold. Moreover, the checking must only start with some delay after motion onset, so that it doesn't trigger right away.
Side note: Stallguard2 (as in TMC2130, TMC22xx,...) only works in SpreadCycle mode. Stallguard4 in the new TMC2209, however, works in SteathChop mode, and if I interpret the datasheet correctly, it works only in StealthChop mode. But given that the Trinamic datasheets tend to leave a lot of room for interpretation, this interpretation might as well be wrong. Nevertheless, I take this as another indication that doing sensorless homing in StealthChop mode is not such a bad idea.
If there is interest, I would clean up my code and submit a PR.