[dsacco]

I agree with the bottom line here, but there is plenty of opportunity for market making strategies without going into high frequency trading (which you're not going to be doing as a solo retail investor anyway). There are opportunities where demand is available but liquidity is disproportionately lower. You'll need a lot of capital, but as a smaller investor it might be worth it for you whereas larger firms might not find it worthwhile (or know about it, yet).

Just a clarification, because it seems like the most mentioned facet of what traders do these days is something with "machine learning" and "high frequency trading", but the actual use of either of those in active trading is small. Even in algo trading, the "machine learning" is very often just rebranded statistics, and not very complex statistics either (think linear regression).

That said, unless you have a real plan to do better than average in the market, you probably won't, so the advice to just invest passively is right on the mark.