Hi there,
I agree 
with you and Awesome leg work you are doing in this. 
The bus fault is the hardest sometimes to ferret out. The debugging also IMO isn’t there yet, It works but seems slow and a little clanky to me. The nRF52840 was way smoother even in VScode and PLIO.
I bet all cash money there will be another BIG release on the SDK to tweak and fix a few performance issue’s users are reporting on the Dev academy support forum.
I get the sense from even the Dev team at nordic that this was pushed hard and Support is just getting in stride. I do like the focus though they have on getting it out and revising to get it right. Seeedineers IMO should do the same.
Keep rolling 
HTH
GL 
PJ 
i say this as it feels like the Zephyr side is ahead of the SDK side or something 