Play to Earn projects are bad because they are inflationary. You imagine it like this. If their projects have good marketing, growth, more players will join, invest first and play their games. The more players play their games, the more tokens will be created in a same time. The more active players, the higher inflationary rate.
If you are not smart, determined and fast with your decision, you will stuck after their tokens were dumped.
You can choose Play To Earn category from Coinmarketcap or Coingecko, check charts and see how those projects have dumps in past months. Their tokens will be dumped in either bull or bear market.
This means that if someone wanted to make money with those coins they will need to enter early and then hope for the game to get popular, but this is risky as if it does not happen you will lose your money as well, and even if you were to get profits it will come from the poor people which joined late and which will most likely not be as lucky as you were, so with this in mind it is better to stay away from those P2E tokens.