I am a freelance motion designer and have run into this issue way too often.
I have my own Business account that I use for my freelance business, but whenever I need to be integrated into another agency's company ecosystem, Dropbox does not allow me to sign into their Business profile while staying logged into my own Business account for local working/syncing on the Desktop app. This can be incredibly frustrating if I am working on several projects at one time, which I often do.
It would be so righteous if Dropbox allowed the use of signing into multiple Business accounts at one time in order to avoid the back and forth switching and to avoid needing to upload files through the web version to ensure backups are consistent/automatically synced on both accounts.
PLEASE!
PRETTY PLEASE!