I just want to know that when you connect and SFTP external storage and share links of files available on it. Then when someone downloads through those links, which network speed will the downloading depend on? The hosted Nextcloud server of the SFTP?
If it depends on Nextcloud, then is there any external that uses their own network speed?
At least a few factors that can add bottlenecks:
Speed of remote person’s machine’s network interface and their ISP
Speed of your ISP
Speed and configuration of your router
Whether your server and router are properly configured
CPU and ram and network interface on your server
Your drive speed and whether it is ssd or slower spinning sata disk or something even slower like usb
How many other people are also accessing your device simultaneously, etc.
Probably other factors I’m not thinking of, but there are quite a few and all of them matter.