Strange Disk Image File (.dmg) problem - deleted files in xyz.dmg do not relinquish file space

Hardware & OS used: - Mac Studio M1 Max 32GB mem 1TB SSD Mac OS Ventura 13.2 - Mac Mini M1 16GB mem, 1TB SSD Mac OS Ventura 13.2 - Mac Mini Intel i7 32GB mem, 1TB SSD, Mac OS Ventura 13.2 **Background**: Currently using Veracrypt software container to store sensitive files. Update files within this secured container (after mounting) with Free File Sync works perfectly. **Objective**: Would like to change this way of operating to Apple’s own software ecosystem by using an encrypted .DMG, created with disk utility. **Followed procedure**: In Disk Utility, select **File** > **New Image** > **Blank Image**, then save with name File.dmg and select location. Select name, select **Size**: 1GB, **Format**: APFS, select **Encryption** (enter password), **Partitions**: GUID Partition map, **Image Format**: read/write disk image, then click **Save** File.dmg was created with a password. Works perfectly, mount and dismount. **The problem/issue on all three Macs**: If I now manually add files to this mounted disk image, all works fine. However, when I want to delete some files, the obsolete files disappear in the Finder view (also when displaying hidden files) but they keep occupying space in file.dmg. You can perfectly see this with the “Get Info” tab in Finder. So my allocated 1GB gets very rapidly full as deleted files don’t hand back available file space to the system. I have tried all sorts of combinations (parameters) while creating a .dmg in Disk Utility, but the problem remains. The only way in which I am able to reclaim the “lost” file space is to manually empty the Trash. I think this is not right as deleting files on an HDD or SSD should relinquish the space the moment the files are deleted and are being placed in the Trash, this pending final deletion. Is anyone else experiencing this problem or am I doing something wrong?