I was in a similar boat for my last few jobs. I realized how easy it is to get siloed into being a "frontend" developer with most companies, as if I wasn't capable of being anything else. I joined a startup that allowed me to build full-stack, negotiated to change my job title to "Senior Software Engineer", then later applied to a backend team at a larger company. This led to CI/CD work which led to a largely Devops role on a Platform team, which has worked out really well for me.

So my journey summed up would be [frontend] -> [fullstack] -> [backend] -> [devops/platform]

I prefer it because you get a lot more high-level visibility on whats going on in your company, and there's a ton to learn, especially since we're using Kubernetes, which is a whole discipline in and of itself. Another benefit is that the vantage point of a Platform-like team allows for more leadership opportunities, which is a good way to get promoted in an IC track and enhance your career in general. So if that sounds interesting to you I'd say give that a shot.

Edit: IMO you will probably need to change companies - even the most growth-oriented, forward-thinking startups seem to forget that developers can learn new skills and will tend to strongly prefer that the thing they hired you for is what you keep doing. Smaller startups are usually more flexible and easier to pivot career paths since they don't usually have specialist teams. It really depends on the company though - I think I got lucky, and had to actively want to move in that direction. Even today when I talk to recruiters and say that I technically have the most years of experience in React, they immediately want to move me to a frontend team. It just be like that.