Anchor Pointer
Moves a layer's anchor point with separate X and Y controls, and keeps it in place when the text changes.
Tutorial, 0:28
Apply it to any layer and set the anchor point in the Effect Controls, X and Y separately. It is made for text layers you might edit later: change the words and the anchor point updates with them. If the text is animated, use Anchor at Time to measure it at a specific frame.
Install it under User Presets, then Transform, and refresh the Effects and Presets panel.