"Relaunch" is a much-abused term that has no formal definition. Marco Palmieri used it to refer to the initial promotional push for the post-finale DS9 novels, the relaunching of the series after a "refit," as it were. And yet even though a launch is a single, specific event rather than an ongoing process, the term "Relaunch" came to be applied by association to the entire post-finale DS9 series, and then by analogy to other post-finale series.
There is no cohesive "TNG Relaunch" or post-finale series in the sense you mean, since the modern, cohesive book continuity didn't emerge until years after TNG ended. Also, the kind of post-finale series that tends to get nicknamed a "Relaunch" is the sort of thing that can only happen after the series is over and the books are free to take their own path. As long as there were TNG movies being made, the TNG books were still in "series" mode, constrained to avoid significant changes in the status quo and mostly limited to standalone adventures rather than the kind of ongoing arc that constitutes a post-finale or "Relaunch" series.