I have the same issue. .Taking it to Tesla will be a completely useless exercise. They study all your logs, driving habits, ask you to a range charge (bring it close to 0 and take it to 100%) 3 consecutive times, and at the end of it all, they just say the battery is looking good and nothing can be done. After performing all of these, I lost a bit more than what it was when I initially took it to them. I have a 75D, and my loss over an year and half with around 24k miles, is 10%. There is no rhyme or logic provided as to why. I have lifetime 285 wh/m... IMHO, no one in Tesla SC understand battery technology, nor can they provide any logical reasoning. I asked them when do I press panic button.. they don't have any answer to that either.. and obviously, degradation is not covered as part of warranty.
I may end up with usable range of 100 miles in a couple of years, and they may still say it is operating within normal median range. This will be an expensive brick pretty soon...