I think the better question is not whether day trading works in general, but whether a specific trader has a repeatable process. Commissions, spreads, competition, and speed all matter, but discipline still matters too. A small trader probably needs fewer setups, cleaner risk, and better patience. The edge may be in waiting, not in clicking more often.

Session timing matters a lot here. I do not want to take a range strategy during a breakout hour or a breakout strategy when liquidity is too quiet.

Good point, I would still wait for confirmation.