It looks really great. Is there something similar for Linux?
The file open dialog is likely the "portal", which works securely across sandboxed applications. Every Linux does have a portal implementation.
In KDE this portal has quite some features, but it could be that some are not available, possibly spec-related or security concern. You can look in the settings though.
EDIT: pinned items are available in the desktop-portal. I have not looked into breadcrumbs, but I like the location bar to be editable straight away anyways.
tl;dr There's a ‘filename’ version and a ‘URL’ version of the dialog. Some things are incorrectly missing from the ‘filename’ version because they're internally implemented using URLs.