Hello @Sovanbera77 

We provided a new pre-release firmware for XX530v V1 here. Please update and check whether it improves speed.

If this doesn't help, please verify and provide more details:

1. How do you access the FTP server, from the local network or from an outside network?

2. What kind of VPN server are you connected to? If you connect directly to the VPN server on the computer or phone, bypassing the XX530v, what speed will you get? If the speed is also capped at 1-3 Mbps, it's suggested to try another VPN server. Selecting a server that is geographically close to you will normally result in increased performance (due to lower latency).