we can simulate the WarpMarker for eg.
* use 'TAB' for finding the next transient (or find it manually)
* use 'S' for split it there
* select all the items you want to re-time with Right Click + Draw selection for eg.
* hold down 'ALT' for stretching the items.
just an idea.
Reaper has Elastique v1 and 2. afaik there is NO newer version of Elastique released. (if they will release v2.1 or 2.2 - i guess Reaper will have it soon)
make sure that you have Elastiqe 1 or 2 set as your default algo: