have a "Costco purchases" sub-category for "groceries". If you ever feel differently, just move it to "home". Your system has to support this though. I did multiple re-organisations in the last 10+ years.

Maybe the right way to do this is to only track accounts, and no tracking of individual txns?

Importing and tracking 401k contributions and stock dividends across multiple brokerage accounts - and then trying to handle timing differences (money in flight)… oof