Perhaps #ProjectSend could be something for you:
https://www.projectsend.org/
Even simpler would be #Jirafeu, which promises one-click file sharing:
https://github.com/Newlode/jirafeau
#Lufi would be an alternative to Jirafeu, that adds encryption:
https://demo.lufi.io/about

All suggestions can be #selfhosted and are #FOSS

Hashtags are for greater visibility :)

@sheepdev