> substantially similar investment

They actually use the word 'identical' instead of 'similar', if that matters. It seems to be a grey area with ETFs, and I'm not a financial advisor, so won't make any further claims.

> You might want to talk to your tax accountant.

Absolutely agreed. You can also just let a reputable robo do it for you if you don't have the time or energy for it, there are multiple. It is what I ended up doing. It's modest but every bit helps.