Closest dropbox / wetransfer alternative on Cloudron?
Surfer can do file/dir hosting but password is for the entire site. Separate sites for clients.
Cubby is simple and works.
Jirefau is pure file, so dirs will be tgz/zip/... archives.
WP can be done with the right plugins too.
Maybe even in EspoCRM if @marcusquinn chimes in.
I'd go Nextcloud for simplicity and it has so many other uses.
Espo does have a brilliant feature in being able to create "Portals", which you can also use for this kind of thing.
Both are good options for long-term shares. If it's just a large file transfer and then delete, then I think you have some other options.
share misc work with my clients.
This is the key part IMO.
Different solutions but clients are often not very tech-literate (yours may be), so it has to be easy.
So, as others have said, Nextcloud probably wins.
Despite being a fat solution for a simple task.
Personally I use Seafile, but it's not a Cloudron app.