My X sleeps overnight and almost never wakes up. So almost zero vampire drain. Power saving on, always connected off.
But before I had a huge vampire drain and my X was not sleeping at all. I finally found why.
After I traded my previous Sig S in for my new X, the Tesla token didn't change. So I changed the Tesla.com password to invalidate old tokens. However, of course TeslaLog kept trying to connect to the Tesla servers with a wrong, expired token... THAT was my culprit. After stopping polling on TeslaLog, my X was able to sleep.
So if you have third party app and not using it, delete the account or in TeslaLog "stop polling" to prevent the app from polling Tesla servers at all. Just changing password was not good enough.