Bottled as a test rather than a habit is the right framing, and worth adding that not all bottled water is suitable. Some is very soft and produces the same hollow result as distilled.
Read the mineral content on the label rather than assuming. Something in the middle range works well and is usually the cheapest one on the shelf.
For espresso machines specifically the calculation changes, because descaling and eventual boiler damage make water choice a maintenance cost rather than a taste preference.