Solid guide and I like the “glass box” mindset: own the file, see every formula, no vendor lock-in.

Only pushback: “institutional-grade” lives or dies on the boring edge cases—splits/dividends, corporate actions, ticker changes, cash flows, multi-currency, and whether your return series is actually clean (no bad yfinance gaps, consistent trading days). If you handle those, this becomes a real tool instead of a pretty dashboard.