I don't run my VPN for ad-blocking (my phone is rooted), I use it for more traditional access reasons.
To copy and paste another reply I just made:
"I ran some tests with the guys in WireGuard IRC which seemed to confirm that the issue is specifically EE limiting UDP whether by QoS or otherwise."
I'll give OpenVPN a go over TCP once I have a chance to set it up and I might even consider contacting EE for info.
I would mind the fact that it limits my throughout to, at best 12Mb down, but when on WG it typically approaches 0 making my device unusable and I've already ruled out the rest of my network.
Another possibility is that they are using naive port-based filters in their traffic shaping rules, and it thinks that any encrypted-looking packets not destined to one of a white-listed set of ports is torrent or other P2P traffic.
If you run the server side of the VPN as well as the client, you can test that possibility by trying other known ports (1194 that OpenVPN usually lives on, 433 if that isn't already directed elsewhere on the target address, ...).
Interesting. I've not noticed performance issues beyond those expected due to signal quality when using work's VPN over a tethered phone using EE. That VPN is using OpenVPN with a UDP transport. Then again it doesn't get used for anything with high throughput so perhaps they only throttle when it looks like bulk transfers are happening or the effect of the throttle just isn't apparent for my interactive use-cases.
> or have you found a way around this?
If they are throttling UDP for your use case then you could try a TCP based VPN (OpenVPN supports this), though there are potential issues with layering TCP inside TCP particularly on high-latency connections so this is not usually recommended. Might be worth a try to compare/contrast though.
I have a play with mine both ways when I finally get round to adding it to my current phone (mainly to use the network level ad-blocker running at home) and see if I can see a measurable difference with each variant.