... it does look like a rim/campy would be easier for me to build as a first bike & maintain...
I have no clue about the toyota/audi/lambo comparisons ...
The learning curve is steeper for disc brakes.
But after sone misses and youtube vids, you'll know how it works.
Never had any of the issues you listed on many frames.
The most annoying though is misaligned brake mounts.
So common that I finally bought the tool to face them.
For the car metaphor.
For road bikes, since I descend often at 80-90km/h when possible, I psychologically preferred to rely on branded frames.
I did ride for few years a Canyon Ultimate CF-SLX, fine.
When a tube cracked just before a big Alpine event, I converted my Carbonda CFR-505 to a road bike, it did ride as fine.
Then got back the Canyon finally replaced, and didn't notice any significant difference.
I moved to an Aethos S-Works now, and... it is fine too. Again not a revolution either, except maybe the number of people telling me how nice my bike is
Each time however they were equipped with hi-end electronic shifting and hydro disc brakes and very good wheels and tires.
Most of us will be happy with the bike they build from a reputable seller here.
And for me the equipment and wheels/tires is what makes the bike.
I'm not convinced the frame is that important.