This is likely something that can differ a bit depending on company and organization, but in general:
- Sales Ops functions are focused on strategies, systems, and processes related to stuff like sales forecasting, quota assignment, sales comp design, sales coverage, and administration/maintainance of a company's CRM and lead management systems. All this is of course done in service to not only enable sales, but also execute on the desired sales strategy.
- Product Marketing's focus on sales enablement is more oriented around development of content, assets, and sales tools that help a sales rep sell a particular product or solution (e.g., sales decks, demos, case studies).
In some organizations, there are sales enablement training groups/teams that focus on developing curriculum, courses, and learning design to help upskill sales reps in different selling methodologies (e.g., consultative sales).