hi @hamt!
Thanks for your message and welcome to the community 
Have you tried or can you try logging? If so, can you tell which steps are taking most of the time?
You can try by prefixing your commands:
PRODIGY_LOGGING=basic python -m prodigy ...
You can also use verbose instead of basic to get even more details.
What recipes are you running? It seems like the issue is with annotation, not training. Any problems with training? Also, are you using any active learning?
Also, some recipes (e.g., relations) do have some issues with larger text (500+ words or more). I do think in general shorter text is better. Here's one set of tips to split up your tasks: