"no autopilot trim and no electrical trim" doesn't sound like a mechanical issue to me, but the underlying issue certainly could be. Of course, things like this do occur, but you would think that on a newly delivered plane that passed Boeing's QC, this wouldn't happen. And, as a pilot, if you see these issues you probably start wondering what else might be wrong. After all, one of the most pointless and horrifying aircraft accidents in recent years (https://en.wikipedia.org/wiki/Alaska_Airlines_Flight_261) also initially looked like a trim issue. Not to mention the two 737-MAX crashes of course, where it was also ultimately the horizontal stabilizer trim that flew the planes into the ground.