I’m facing the same issue and I didn’t find any piece of documentation that clears out what you’re asking.
In my case, I have a ‘News’ custom post type with a single ‘meta key’. I just want to know if the Query Loop block is capable of filtering by meta key. I already checked the block.json file of this block and didn’t find anything. The solution would be to create a custom block.
https://github.com/WordPress/gutenberg/blob/trunk/packages/block-library/src/query/block.json
