while in the end it is your tax return and you have responsibility for the result, what I am pointing out that Vanguard takes the position (at least in the specific example I offered and I suspect others mutal fund / ETF examples) that a mutual fund and a ETF are not subtaintailly identical and do not invoke wash sale reporting under the circumstance we are discussing.
Here is Fidelity's viewpoint. While they don't state unequivically that mutual funds and ETFs are not substantially identical, they make the case why they are not identical. We don't know how they operationalize this in their wash sale reporting; however, Vanguard does operationalize this viewpoint and doesn't report these situations as wash sale losses (again in at least the one example I provided but that means there are other examples).
https://www.fidelity.com/learning-center/investment-products/etf/tax-rules-for-losses-etfs
"It could also be argued that a sale of mutual fund shares at a loss, followed by the purchase of an ETF that is similar to the mutual fund, is outside the wash sale ban. The ETF price usually reflects the prices of the stocks it holds, whereas mutual funds shares tracking similar holdings may not have the same underlying value. In addition, there are different fees or other charges associated with mutual funds versus ETFs."
it would be worth calling Vanguard and ask about their wash sale reporting on the two funds in question.
