I'm a newbie to these forums, and to Linux so please excuse very a basic query here - but I have used qBittorrent 4.3.1 on Windows 10 via NordVPN P2P servers for some while, and I'm used to getting max download speeds of around 2MB on my Vodafone home network connection. I also have a Linux Mint 20 laptop running on the same network via the same VPN on which I installed the same version of qBittorent. That gives me a download speed of 2KB to 200KB.
I've been through all the settings as thoroughly as I can, and the two apps appear to be set up pretty much as identically as is possible given the different OS.
Does anyone have any advanced tips for getting better speeds?
Just to add insult to injury, the registration form for this Forum wouldn't work in Linux. I'm using Vivaldi for the browser - the form kept refreshing back empty with no visible error messages. When I tried to use the Contact form to report the issue, that failed too! Tried it out on Windows and everything works.

I'm back on Windows for the time being so I can talk...
Gaz