Same thing happened to me. 2015 SR5, stock tailgate.
Struts worked one day, completely dead the next.
Took it into the dealer and they replaced the struts in a couple of hours under warranty.
No questions asked.
The shock size is 2.5, see link.
Toyota 4Runner 2016-2010 Front Shock - 2.5 Factory Series Coil-Over IFP Coil-over Shock | FOX
The lift is 2 inches.
Yes, it rubs at full lock.