The tell is which rooms are photographed
A genuine cosmetic project gets photographed. Dated kitchens and worn carpet are not embarrassing, and an agent selling a fixer will happily show you a brown bathroom because it makes the price make sense.
What is missing is the signal. No photograph of the basement, the furnace room or the panel is the thing worth noticing, because those are the rooms where the expensive problems live and there is no aesthetic reason to leave them out.
Cosmetic work is cheap. Systems are not.
This is the whole distinction, and it is worth being blunt about the gap.
Paint, flooring, cabinet fronts and light fixtures are a few thousand dollars and a lot of weekends. A furnace at the end of its life is $3,500 to $8,500, and it cannot wait for a weekend. An undersized electrical service is $2,000 to $4,000+ to bring up to 200 amps, and it blocks half the renovations people buy a fixer to do.
The question that separates the two
Ask the agent this, in these words: which of the mechanical systems have been replaced, and when? The furnace, the water heater, the roof, the panel and the supply plumbing.
A seller with a genuine cosmetic fixer answers happily, because a newer furnace is the argument for the price. A vague answer to that question, in a house being sold on its potential, is the whole story.