Dropbox Backup - does it move the Documents folder?

I'm backing up my Mac to an external hard drive with TimeMachine. I would also like to back up my Documents folder to the cloud. Dropbox Backup sounds good – but will Dropbox move my Documents folder to within its Dropbox directory? And will this prevent TimeMachine from backing it up? I want my Documents folder to stay where it is. In my User account folder. And I want to work on my files locally (not on cloud files) – and for these local files to get backed up to the cloud in the background. I've tried OneDrive and it moves the Documents folder into the OneDrive folder. OneDrive also can't cope with folders starting with a space (and I have a lot of folders on my Mac starting with a space!). Will this be a problem in Dropbox? (I've tried iCloud Drive Desktop and Documents twice and both times it has completely knackered my Mac – because the files live on the cloud, large files can clog up the synching and then Finder goes glitchy)