From what I understand, only Spine-Unity runtime has root motion support. Are there plans to expand support to other runtimes?
Spine 4.2 Runtime Root Motion Support
Bad Spinebot 
However, it is kinda right. We currently don't have root motion support on the spine-ue roadmap, mostly because it hasn't been requested before and because runtimes other than Unreal seem to have substantially more use.
That said, I've created an issue for it here:
EsotericSoftware/spine-runtimes2631