SMB, WebDAV and FTP services slow over Wireguard

Technical Support for Routers VPN, DNS, Leaks
1

I use file sharing services over Wireguard (Flint-2), and ANY file sharing service is BAD.
For example, FTP 36 KB/s, smb 30 KB/s.

Fast.com result (over Wireguard) is:
Internet speed:
download - 2.1 Mbps
upload - 9.9 Mbps
Latency:
download - 217 ms
upload - 183 ms
The test result for ok, It's 4000 km away.
ISP plan speed 200 Mbps (up and down).

So I try SMB, WebDAV, FTP - everything is sucks. Can't understand why my filesharing speed is SO LOW. I can't use my Network storage (ssd via usb on router), and NAS over LAN, can't sync my photos.

I can use web (even 4k youtube), but can't do my job (ftp and smb still use 35 kb/s, no matter I watching youtube or not). Looks like somebody slowed down file sharing protocols.

2

I would say even your internet speed sucks - no matter if it's 4000km away or not.
So you might check the MTU settings and adjust them to lower values to receiver better speed.

SMB isn't great at working over VPN all in all. Latency will make it pain to work with.