Playing 1000 hands of blackjack after memorising basic strategy should be compulsory for new traders. If we are talking small edges then your comment about 300 hands not being sufficient holds. If you have a large edge though this will become evident over a smaller sample.
If i asked the question as to how you would know if you had an edge or not, what would you say? Could you define it? How specific can you be? Genuinely interested, since this is a question i often ponder.
Yes. Like a bank trader who has access to specialised orderflow information unavailable to retail traders for example.
Would you say without such info and just using charts, we're all essentially just flipping coins, and don't have an actual edge?
Or a retail trader who understands how order flow works and can piece together likely order flow in the book via reverse engineering TA, understanding the macro environment, understanding important fundamentals, and understanding how the weak hands lose. It's really not that hard. All in all, if you've been trading 3-4 years full time and still consider yourself struggling, you should really accept defeat and find a new career.