I just migrated some projects from DBeaver 6.1.4 to 7.2.3 and the File > Export/Import options worked flawlessly.
The full workflow is:
File > Export, under "DBeaver", select "Project", click Next
Select the projects to export and click Finish
Copy the output file (by default, it is generated in home folder) into the machine where the projects will be imported
File > Import, under "DBeaver", select "Project", click Next
Select the file generated in the previous steps, it will automatically load the projects from it.
Select the projects to import, if there is any name conflict you can change the name of the imported project. Click Finish.
IMHO, very complete, easy and straightforward.
Update: after a few days of working, I realized some of the connections were not imported. I still don't know why, but it seems to be a bug. Just double check your connections after exporting and importing.
If you're using the Windows Store DBeaver CE Application on Windows 10 the workspace folder is different because of the app sandboxing and looks like this: