I feel like this is a known problem on High Sierra, but I can't delete my BOOTCAMP partition to gain "Free Space" and I also can't expand my APFS container that contains my MACINTOSH HD. It's like they've turned into seperate hard disks, and I can't move over the space from the old file system to the new one. This is what I find when I type diskutil list into terminal:
I tried manually deleting the BOOTCAMP partition using terminal, and then expanding the container: I tried using the diskutil apfs resizeContainer. But I got an error saying that the target disk has no space (i.e. it doesn't detect the free space). Any solutions?