No pressure!
In terms of photos, can do but not much to see, no extra hardware beyond the pisound hat directly connected on top of the pi 4.
Meanwhile I dived in the archives and found your helpful post on gpio readall.
A newer replacement is available which works across Pi versions.
I used this to snapshot the GPIO state between button off and button on. It shows GPIO17 again.
Output is below:
buttonon (2.0 KB)
buttonoff (2.0 KB)
diff (310 Bytes)
So as far as I understand, this is no different than connecting a button directly to the relevant GPIO pin and ground. My guess is it’s now a config error on my behalf.
Regards