Oh bummer. You just spent 4 years building an extremely solid base in multiple different aspects of programming. How could you possibly ever be expected to find unique specializations?

Tldr: University is a foundation you're expected to build on it.

Studying at a university is not a fancy job training.

Do whatever pays your bills, and learn what interests you. Sometimes the latter will help with the former, but it would be silly to depend on that.

Either learn the hottest new thing or the legacy thing everyone is stuck with, both will always be in demand. But the whole point of the field is to always be learning so starting a good habit of that now is key. Read and research and tinker. Contribute to open source. Follow people and projects on GitHub. The best software engineers are looking for problems to solve and then learning the tools required to solve them, not looking for problems that fit the tools they already know.

The way out is to learn more. MERN/MEAN is a flash in the pan relative to the trajectory of the industry. You have to keep learning and never stop. Yes, learning Python will help you get more jobs. But so will learning C#, or Java, or getting AWS certified, or Azure certified, or learning tensorflow, or learning perl.

Learning more things will open up more job opportunities. It always has, it always will. And your local job market is not big enough to accommodate all skills, so if you want to stay where you are, try to assess what skills are present in the job postings you want and learn those skills.

I want to college and got a comp sci degree but they didn't teach me any frameworks. I had to learn everything industry-related on my own. I share this because you do not need a school to give you a degree that says "this person knows python". But you do need to spend your free time learning more things if you expect to adapt to the constantly changing tech landscape.

I don't get the concept of "learning" a specific programming language, you can't just sit down and learn the entire thing at once. You use it, google its weird quirks whenever you come across them and get better with it over time.
I've always been really language agnostic, which led to me being shifted into a Delphi team and then into a Typescript/React team. Didn't know anything about those languages when I entered the team but someone who's willing to just try their best can be a lot more desirable to a company than someone who thinks they can't do something just because they didn't spend time learning it "properly" first.

Also, might just be a regional thing, but the last time I went to one of those "I just finished university and want to network with companies" events, like 70% of the CS graduates were looking for Data Science positions. Seems like it's quite the saturated market.