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By default, Lightroom will use the most recently selected Destination Folder location for the subsequent export, regardless of the currently active folder or collection.
There is a dropdown menu accessible by the small downward triangle next to the Destination Folder path; Lightroom remembers 20 recent export destinations so you can select from this dropdown.
You can save a Preset that will include the destination folder.
You can also use the Export With Previous command, which will use all the settings from the last export.
Though the Edit in Photoshop command, by default, puts the exported Edit file in the same folder as the Original, the File > Export command does not include an option to specify a subfolder within the current folder as the default export destination.
If you're exporting to a different folder than the previous export, you must specify the destination folder.