Tlhokaina It would be a crime to have your phone alter responses to cell tower pings by a few milliseconds?
As areaman indicated, round-trip time is no longer a primary metric for towers determining handset location. Angle is very important (to determining location but also to network efficiency) and angle is difficult for the handset to manipulate.
Also, if round-trip time were a major component it would probably be timed at the radio level, I.e., under control of firmware that GrapheneOS can't easily adjust.
This idea shows up from time to time, but it is important to keep in mind that the cellular network is literally designed to track mobile device location. In many jurisdictions carriers are legally required to achieve some level of accuracy, in the name of providing data to emergency responders.
The cellular network is convenient, but if what you want is to not be tracked, smart people have worked hard to make it disappointing in that regard.