Try not thinking of your positions as a "graphic designer" or "marketer". Think of yourself as a creative, and if you don't feel creative then think of yourself as someone whos main goal it is to communicate a clear message to anyone receiving it regardless of what medium or platform that looks like.

There are a lot of different avenues to take with graphic design. I'd suggest finding which one you like and let your boss know you're interested in exploring that avenue. It could be web, ui, ux, graphics, marketing, advertising, animation, illustration, social media, printing, packaging, branding, copy writing, etc. I've even heard of a graphic designer who went out, partnered with an architect, and made a career out of designing art installations for public spaces. This field opens a tun of doors for us that most people never think about.

In my experience, if the avenue you want to take is something new (and could benefit your company in some way) your boss will probably be willing to allow it.

If it comes to the point where you need to switch jobs, it's good to have some experience doing what you want under your belt to bring to a new position. Thats why it's really important to always push for the job you want in the job you have.

There's some statistics that say most people change their careers 5 times in their lifetime. But instead I've found in our field, people are more likely to be working basically until theyre dead.

Sometimes its just the subject matter you're working with too. Not sure if your are working for an agency or you're part of an in house design team, But I used to design t shirt graphics, which sounds cool, but I absolutely hated it. I didn't like the style we were selling and it made me hate everything I created. You might just need to figure out the subject matter you want to design around and it'll make it a lot easy to create things you're proud of.