The bug that has plagued me for more than a week now was an easy to miss typo at a rather obvious location.
I read through the firmware source of the SDR, the documentation of the platform it was built on, found two different unrelated bugs in the create I am using, but it was a typo/possibly autocomplete fuckup (to_be_bytes would be listed before to_le_bytes if purely alphabetical, but the other calls in the function were correct, so very easy to miss).