Looks like IPv6 routing from Richmond, VA to Grafton, WV has issues. IPSEC tunnel between gets less than 5Mbps over IPv6, switching endpoints to IPv4, I get the full 25Mbps down capability of the WV connection.

Traceroute looks like below:

Tracing route to 2001:558:6035:3c:79bb:f773:ab2:6bcd over a maximum of 30 hops

  1    <1 ms    <1 ms    <1 ms  2601:5ca:c301:4c90::1
  2    11 ms    11 ms    10 ms  2001:558:4053:b::1
  3     7 ms     7 ms     8 ms  2001:558:182:112::1
  4    20 ms     9 ms     9 ms  ae-45-ar02.staplesmllrd.va.richmond.comcast.net [2001:558:180:2005::1]
  5    26 ms    30 ms    24 ms  be-21508-cr02.56marietta.ga.ibone.comcast.net [2001:558:0:f787::1]
  6    22 ms     *       23 ms  be-1202-cs02.56marietta.ga.ibone.comcast.net [2001:558:3:12::1]
  7     *       28 ms     *     be-1211-cr11.56marietta.ga.ibone.comcast.net [2001:558:3:2::2]
  8     *        *        *     Request timed out.
  9     *        *        *     Request timed out.
 10    36 ms     *        *     be-1402-cr02.ashburn.va.ibone.comcast.net [2001:558:3:2d::2]
 11     *        *        *     Request timed out.
 12    39 ms    43 ms    42 ms  2001:558:380:29c::2
 13    42 ms    45 ms    50 ms  te-5-1-0-cbr01.taylor.wv.pitt.comcast.net [2001:558:382:fe58::2]
 14     *        *        *     Request timed out.
 15     *        *        *     Request timed out.
 16     *        *        *     Request timed out.