okay , so to confirm :
if i want to move all the projects from one sandbox to other , i have to open and publish each project individually with the help of VS Code app.
There is no other way where one can move all the projects at once.
Also the use of multi-root workspace is just to work with multiple projects together at one window. you cannot commit the projects using that code-workspace file, you have to open that project individually and then commit to azure devops.
am i right?