But as I need to use mixed files/folders sorting I really miss features for folders: To have them stay on top or at least some of them.
That's why pinning folders to top would be good.
Other would be similar to that of Windows File Explorer:
Arrange folders to top and files sorted by date modified:
To sort files by Date Modified while keeping all folders pinned at the top in Windows File Explorer,
switch to the Details view and click the Date Modified header followed by a Shift + Click on the Name header.

Folders always - but not when mixed, but always.
Folder pinning feature might be the easiest and most handy addition to folder sorting issue?