OSXRESERVED partition (
disk0s3) is created by the Boot Camp Assistant to hold the files needed to install Windows. The partition is suppose to be deleted during the installation of Windows. If Windows has completed installation and working correctly, then you can delete this partition. The commands to do so are given below.
Note: These commands may need to be prepended with a
diskutil erasevolume free none disk0s3 diskutil apfs resizecontainer disk0s2 0
Note: The answer below applies to Macs which UEFI boot Windows. If you have an older Mac which legacy BIOS boots Windows, then you should should not use the answer below.
If the above commands are completed and the Mac is restarted, then your question will become a duplicate of the question Missing around 20 GB of Space on MacBook, at least in terms of a solution.
To add the remaining free space back to the partition containing macOS, the partition containing Windows would have to be first moved to the end of the drive. There are third party tools that can move Windows partitions. However, not all are compatible with macOS. According to the other post, there are two possible compatible free tools available. These tools are outlined below.
GNOME Partition Editor (GParted). A Linux based bootable USB flash drive can be created containing this tool. After booting from the flash drive, the GParted tool can be used to move the Windows partition. If you build the bootable USB flash drive using the zip file downloaded from GParted, then both a keyboard and a mouse (or similar device) is required. One disadvantage is the keyboard and/or mouse may be need to be wired to use this tool. However, if you can boot from a Ubuntu installer flash drive, then only use of a mouse is required. One advantage is this tool does not have to be installed into Windows.
MiniTool Partition Wizard. This tool is installed into Windows. To move Windows, the Mac reboots and performs the move without user interaction. One advantage is any existing keyboard and mouse (or similar device) can be used. One disadvantage is this tool has to be installed in Windows and therefore will still exist on the drive after you are finished moving Windows.
Note: Before attempting to move the Windows partition, the Windows
chkdskcommand should be applied to the NTFS volume in this partition. This can be accomplish by booting to Windows Recovery Environment (Windows RE) and entering the command below.
chkdsk c: /f