If you decide to mine the coin with CPU, you need to find the potential coins that can get a pump in the next bull run. But I don't think that it will easily to find the coins since right now, many coins are looks like having the potential to increase but we don't know which one that can increase later. You can continue to mining every coin with your CPU, but you should have a big hashrate to earn nice rewards. Without having a big hashrate, you won't get a nice reward, and you should think about the electricity fee that you should pay unless you have free electricity or cheap electricity fee.
It doesn't matter if the CPU mineable coins are rubbish projects because as long as you can get the profit from the coins, you can mining that coins without thinking anything. But once again, it is difficult to find the potential coins which can increase in the next bull run. Good luck to you