To answer your question: it is not you, it's them. Still, rather than over-emphasizing that you don't want to do frontend, spend more time getting a feel for how the company operates during interviews.

I like to ask things like "what are the biggest technical challenges/focuses for the next 6 months?" And "are there any projects or initiatives you would want me to work on right away?" And "if I'm successful at the roles, what sorts of things would you expect me to accomplish in the first half year or so?"

Those all give you more info than the answers alone. I always look out for companies that are always on fire/reactive as a red flag. Good companies will have objectives and be hiring you to help accomplish them. Bad companies will have a put crew tackling tickets "as they come" and any actual projects keep getting superceded by critical issues or user requests that are over-prioritized.

Lastly and most simply, just ask employees there what they are working on and how they go about assigning tasks. If everyone is touching a the codebase and that's not what you want, avoid the role!