They're not legit. They're not profitable. So, forget about it. Don't even consider profit because it doesn't work.
Since you're curious about Bitcoin mining, you might also stumble upon cloud mining. You dismiss that as well.
Just keep on doing your research and asking questions if necessary. Your "little knowledge" will soon grow. At least you didn't hop right into it before asking for "honest insights or advice". That would have cost you the most powerful Android phone.
But, hey, do you even read the responses in your threads?