A share price is the market's discounted estimate of every future cash flow a business will produce for its owners, adjusted for confidence. A wonderful company at a price that already assumes wonder is a poor long; a collapsing company at a price that already assumes collapse is a poor short, and often a violent squeeze.
There are three ways to be right: a variant perception on the numbers, a variant perception on the multiple, or time arbitrage — agreeing about the destination but holding through a period others cannot.
Longs and shorts are not mirror images. Payoff shape, index drift, borrow and dividend carry, and reflexivity all cut against the short, which is why bearish fundamental work is usually best expressed with defined risk and a defined clock. "Overvalued" is not a short thesis; a short needs a mechanism and ideally a date.
Educational, not investment advice.