Can I backtest without connecting a broker?

Good question. The part I'd verify first is the exact behavior around whether a backtest can be run using only local data without connecting a broker account. I wouldn't assume the live behavior until it's confirmed in the documentation or a small paper test.

Backtesting works perfectly even without connecting to a live broker.

Correct. Backtests run off historical data and don't require a broker connection. You'll need a data source for the symbols you want, but nothing gets sent to a brokerage. The connection only matters once you go live or want live-feed paper trading.

Worth noting that offline data has its own quirks — check whether your history is adjusted for splits and dividends, and how gaps or missing bars are handled. A clean-looking equity curve on dirty data is just a distribution of artifacts. What symbols and date range are you starting with?

One thing you can do entirely offline while you learn: run the same strategy at two or three position sizes and look at the drawdown, not just the final return. Halving size roughly halves drawdown but only shaves return proportionally too, seeing that tradeoff in your own numbers early saves a lot of pain later.

Nice that you want to understand the workflow before any money is involved, that's a patient way to start. When you do eventually connect something, notice how differently the same red bar feels. That gap between backtest and live is mostly emotional, not technical. Have you thought about how you'll react the first time a tested strategy loses for a week straight?