Do you actually want to mine properly, or just "use your CPU/GPU power to get coin eventually"? I ask because using something like NiceHash to mine a shitcoin then converting that to Bitcoin would get you coin without you having to buy a proper miner or waste brain power trying to figure out the most optimal thing to mine with your existing hardware.

If you're morally opposed to shitcoins then I'd buy a used ASIC miner on eBay and join a pool. You can get little USB miners for cheap but they have really terrible hashrates so I'd be amazed if you even made back the cost of them.