Can profitable algorithmic traders enlighten me?

Hey so I'm new to algo trading (~ 2 months). I'm reading books and doing shit loads of research, and I keep hearing conflicting answers from professionals about something. Can people who consider themselves profitable in algorithmic trading please let me know: is it possible to develop a profitable trading strategy, whatever that may be, using only a single time series of OHLCV data. I.e. not trading a massive universe of stocks/cryptos, not using L2/L3 or tick resolution data, etc. I have fairly extensive knowledge of markets and economic fundamentals, but limited knowledge of coding and backend infrastructure (im working on it lol), so certain strategies are currently out of my reach. The reason I am so confused is that I hear established traders, the likes of EP Chan, etc, say that simple is often better, but I also hear so many people saying how impossible it feels. Are those people doing too much, doing something wrong, or am I misinterpreting what they mean by "simple"? FYl, pretty much my end goal would be a few thousand dollars a month, so I would have essentially no liquidity constraints.