If you're looking for alternative to the Dropbox client application, you should definitely try what Maestral has to offer to you.
Nextcloud Hub 22 introduces approval workflows, integrated knowledge management, and decentralized group administration.
Croc is a free and open source command line tool that allows any two computers to simply and securely transfer files and folders.
Warpinator allow you quickly and easily to transfer files between Linux PCs, Android phones, tablets, and other devices.
The collaboration between Nextcloud and OpenProject will offers enterprises a data sovereignty and increase in productivity.