I am blocking out geometry for image projection, directly imported from fSpy, meaning I must regularly snap to the camera viewpoint (Num 0) in order to align my geometry to the image features.
So far so great, especially with the snap and merge features of Blender 3.6, however, when I started working on the details of these windows, I subdivided the plane, and I want to take that new edge and precisely align it to an edge feature in the image, so, as with everything else I've modeled so far, I select the edge, then G, X and I move my mouse horizontally across the viewport in the opposite direction that I want to move it, aligned to the X axis.
However, instead of moving as expected, it crawls slowly, which is not ideal, but would otherwise still be fine since I can continue my cursor across the entire width of the viewport, "overflowing" it multiple times. However, past about the second overflow, the movement becomes even more granular, but more disconcertingly, Blender seemingly starts taking the absolute value of my mouse's X movement in the direction I originally started moving the mouse, meaning no matter what direction I take my mouse now, it will move in no meaningful way, making it impossible to align the edge.
Note, that the context under which I made this particular edge seems to matter little. What does matter is the distance of the edge relative to the camera. The only areas where this issue generally arises is anywhere close to the literal edge of the camera viewpoint window (closer to the camera).
This whole thing feels related to the "slow navigation zoom" issue as asked on here already, but some of that advice has either done nothing or does not apply to me. For instance:
This answer describes details about the slow navigation and how to "reset" its origin (Num .). Pressing that while selecting the edge makes no difference. Their other advice to just not use the camera viewpoint I cannot take, as that's literally the whole basis of modeling for this project.
This additional answer lists more of similar solutions, all of which I have tried, with the same primary caveat for my use, but I do want to point out I have Auto Depth enabled in preferences.B
EDIT: Per request in comments below, here is the blend file link.

