I think I've still got my HE IPv6 t-shirt somewhere, from when I completed their readiness quiz so years ago!
Edit: I actually decided to set up a tunnel, just to see how well it worked, and it turns out my ISP supplied router won't forward the protocol 41 packets anyway, so that's a total no-go.
I suppose I could probably set up a small VPS and Wireguard vpn, then forward the IPv6 packets that way?