> most of them miss one or more of F keys, symmetrical meta keys, standard navigation cluster layout, volume buttons, and so on

This is why I made the gallery -- it's an easy way to compare a lot of options, even if not all options have filters.

I have just added the C989 Ergo, which was mentioned elsewhere in the discussion. That seems to be the closest mass-produced, mechanical keyboard to the MS Natural: https://c9ergo.com/