Short answer
Yes. Add as many destinations as you like, each with its own provider, bucket, keys, public URL and path template, and switch between them from the menu bar panel.
The destination selected in the panel is the default. It's used for drag & drop, pasting and the global shortcut. A common setup is one bucket for screenshots and another for client files.
The library can filter your upload history by destination, and each record remembers where it was uploaded, so deleting a remote file always targets the right bucket.