GPU mining itself is not a direct threat to your PC, but it can cause damage over time. The main issue is that most GPUs rely on auxiliary or attached fans, which can wear out faster when the GPU is used for extended periods. To prevent any damage to the card, it is important to clean it regularly. Fortunately, the Ethereum Foundation has promised a cryptocurrency network that will consume much less power and GPU.
Alternatively, miners can switch to one of the many other cryptocurrencies that are still actively mined. It is likely that there will always be cryptocurrencies that use the tried and tested proof-of-work approach to get off the ground, meaning that we will never be completely free from the power and hardware requirements of cryptocurrency mining. For example, one miner had a mining platform in his brother's company that allowed him to mine (he had an empty room for mining, and that room reached temperatures of around 40 degrees Celsius in the summer). Some of these issues are reportedly caused by performance issues at Samsung, some due to semiconductor shortages caused by the pandemic, and others by increased demand for cryptocurrency mining.