I did a bit of digging - and yes, StealthChop is an issue when you can’t configure the TMC drivers.
You can’t turn stealthchop off without UART control of the TMC stepper drivers. What ends up happening is that the TMC driver goes into a shutdown mode, and the printer will just stop extruding.
I don’t know what model steppers are affected by this issue - or which specific models are known to work. I believe it was disabled by default because of the number of users that had affected steppers and the printer would just fail to print.
If you happened to get hold of each of these variants of boards to test (I don’t know anyone who has them all), then it’d be possible to do testing as to what is supported and what is not.
I believe part of the issue is that the stepper should be configured as TMC2208_STANDALONE - and not TMC2208 for Marlin, as TMC2208 mode assumes UART control of the stepper.
As far as the actual PCB mainboard goes, all steppers are connected as if they are A4988 drivers.