Thanks for the pictures, I think I understand it perfectly now.
The shortcut can be called something along the lines of “Select one level deeper”.
Another challenge is that there’s currently no way in Dynalist to select a parent without selecting its children. All the current behaviors assume that when a parent gets selected, its children are selected too. The children are part of the parent in the context of selection. So, we’ll need to go through all the things that relate to selection and make sure they work correctly.
By all the above I don’t mean we’re not doing it, just saying it’s more complicated under the hood than just adding a new shortcut. We’ll have to change a lot of things in order to achieve this, and re-consider some existing behaviors (e.g. should Ctrl+Click select only the parent or the parent plus the children?).