Nemo/most file explorers have a remote server option. For nemo, “Files > Connect to server”. Once configured, you should be able to view your server files from your file explorer and uploading files should be as easy as drag and drop. I’m pretty sure nautilis has something similar too! https://lemmy.world/pictrs/image/19692bf8-91fb-4d55-bb23-982e8f94ba03.png
It’s not the best for security because if someone gets your computer, they can access your server through the file explorer. But it’s fast and convenient if you are already using your file explorer.