Hmm the paint issues are not really normal IMO. I don't like Qatar in general (nor their airways) but paint that strips that much is definitely substandard and could cause hazards. A rough body surface can increase drag a lot, flecks of paint can be ingested and build up in the engines or other moving parts (e.g. flap/slat actuators). It could clog sensors leading to other failures (most airplane crashes are a combination of many factors). But in general it's just a very bad thing for a part of a plane to be in a state it was not designed nor tested to be in.

I've been a pilot and I would not be happy flying a plane in that state.

Don't forget even NASA has said things were perfectly safe when they were not, leading to two tragic fatal accidents. Boeing insisted MCAS was totally safe until the second mass fatality. I don't buy that stuff. You don't fly a plane in such a state.