Short version is: Place a Smith (or have all of them do it for all I care) that can do specific prefix and suffix. Example say I want a sword that has “Demonic” “of the Binding” on it.
Have the cost higher for specifics than random channels. Hell make it a challenge to find and unlock the smith even.
No getting around the RNG of actual stats, but at least we get to narrow the field down to something we want/need.
shrugs food for thought