I am also a non-expert, and am sympathetic to your argument, but I don’t think there’s any reason to believe that whatever fix is proposed wouldn’t account for

I am also a non-expert, and am sympathetic to your argument, but I don’t think there’s any reason to believe that whatever fix is proposed wouldn’t account for the type of risks you are concerned about. All of the risks/concerns you mention would be relevant to any sort of mechanical work on an aircraft, and that is a field of engineering that on the whole has an impeccable record of safety and rigor. Again, not an expert, but from what I understand the issues with the 737 max were software/design related.