This will vary from company to company depending on what industry you’re in, the make-up of your product portfolio, what your go-to-market and sales strategy looks like (are you strictly enterprise-focused or SMB-focused? Do you sell across all segments? etc.), the overall stage of the company, and probably many other factors.
At Sprout, we started with a dedicated Go-to-Market team that was made up of essentially product marketing generalists who owned a large swath of responsibilities. This team was myself and one other person to start. It has grown to 5 focused on go-to-market (not including myself) today. Organizationally, we aligned a Product Marketer with a Product Manager and set the expectation that they become domain experts on that specific product or product area. As we were scaling, that product marketer was responsible for supporting their product area with core product positioning, product launches and release management, various sales enablement efforts, assisting with in-app copywriting, executing internal product enablement (technical trainings, demo environment, etc.). The list was really quite long.
Over time, as our company has grown and stakeholder needs have become more sophisticated, we started to see areas where we either needed to add specialization on our team, or we could actually handoff some of that existing work to other teams that were growing and establishing specializations themselves. For example, we (Product Marketing) added a dedicated Competitive Intelligence person and a Sales Content Writer. We grouped them under a sub-team we call Sales Readiness. This mightly team of two covers competitive intel, win/loss analysis, analyst relations and the production of all sales assets (slides, sell sheets, case studies, talk tracks/objection handling, etc.)
At the same time, our Sales Org and Product Team were growing (fast!) and they built out a focused Sales Enablement team consisting of proper sales trainers and a pre-sales Solutions Engineering team. We saw this as a huge opportunity for partnership. Both of these new teams allowed us to handoff ownership of many responsibilities like sales and technical trainings and the upkeep of the demo environment which had become large efforts.
The important thing to keep in mind is to not bite off more than you can chew. It's easy for Product Marketing to be the catch all for any content, strategy or initiative that the Product, Sales and Marketing teams need supported. Be intentional in where you dedicate your time/effort and work with your stakeholders to priortize which areas you can expand into as you grow.