How to access nested fields in wixData.query?

I couldn’t find anything in documentation, but googling around led me to this dotted notation approach:

await wixData.query('Stores/Variants').eq('stock.inStock', true).find().then(results => results.items)

But it doesn’t work:

"Unknown token stock.inStock -> Map($eq -> true)"

How does one run a query to get, for example, all inStock products?