After moving house came back to VM, openreach network was only 20Mbit in this area, which is very sad. Got super Hub 4 with fan in it! currently HE tunnel is working fine, getting ~200+Mbit for multi-stream download and ~32Mbit for uploads, https://www.thinkbroadband.com/speedtest/1625581719833838755 this is over wifi with temporary network setup (haven't had my server cabinet set yet)
To try and add a bit more data to this, I'm on bagu-cmts-16 (which is a Cisco) and confirm I see NO router-advertisements from my Virgin Hub 3 in modem mode 😞. My area is a DOCSIS 3.1 area, as M1000 is showing as available at my address.
In other news, I have tried a he.net IPv6 tunnel a few times over the past 4 years, and consistently get shocking (<20Mbit) performance on IPv6 traffic, while getting 370Mbit+ on IPv4.
Routing a /64 over a Wireguard VPN to a Linode VPS gives me 350Mbit, presumably losing a bit due to the overhead.
L2TP to the same Linode VPS was giving me 350Mbit for a little while, but then out of nowhere started behaving like the he.net 6in4 tunnel.
It was fun to experiment, and I've been tempted to keep the Wireguard tunnel up and running, but I'm back to native v4-only at the moment. That said, I had no issues with the /64 that Linode gave me, and Netflix etc worked OK without detecting any VPN (and I did verify it was using the IPv6 block). Thankfully my area is OK congestion wise, and I believe I'm on a pretty quiet segment, so even the single-threaded nature of a tunnel wasn't causing any major loss in performance.