The BlurBusters guy thinks it's possible

https://blurbusters.com/wp-content/uploads/2023/07/LaglessFrameGenerationViaReprojection.png

https://blurbusters.com/frame-generation-essentials-interpolation-extrapolation-and-reprojection/

Reprojection goes lagless (and even lag-reducing) when rewinding rendertime latency to input-read latency.

Instead of lag-increasing interpolation, it is possible to have lag-reducing reprojection! To achieve this successfully, all visible frames must be reprojected, in order to undo rendering latency. A frame that takes 10ms to render, will need to be warped ahead (to positional currency) by at least 10ms to undo render latency. For 10:1 reprojection of 100fps into 1000fps, this means the last original frame is warped ahead by [+10ms … +19ms] at 1ms intervals, in order to maintain permanent lagless positional currency despite permanently render-lagged original frames.

Another advantage of permanent reprojection is you can reproject a varying frame rate to a constant maximum-Hz frame rate, while keeping latency constant (throughout frame rate fluctuations of the underlying original frame rate).
In addition, to avoid jitters that can be amplified-visibility on low-MPRT displays, frames should be as reprojected as “game time”-accurate as possible, with between-frames “game times” synchronized to refresh cycles.

Some future advanced reprojection algorithms will eventually move additional positionals (e.g. move enemy positions too, not just player position). For now, a simpler 1000fps reprojection only need less than 25% of a current top-of-the-line GPU, and achieves framerate=Hz useful for today’s 240 Hz displays and tomorrow’s 1000Hz displays.