Currently I have an year of experience. My current tech-stack consists of Spring boot (Core,Data,MVC), spark, AWS, jenkins and native images deployed on ec2 instances.

I've identified some technologies and tools I plan to learn in the coming year(s) like containerization, Message queues, Microservices architecture, API Gateways, a deeper knowledge of the nuts and bolts of Spring core, other frameworks such as Quarkus, Micronaut, alternate openJDK implementations like Azul, Terraform, Helm, Istio etc

My first question is should I stick to mastering the backend over the next 3-4 years or Do I need to give equal attention to frontend as well? Can I survive being a "simple" backend engineer? In which role could I bring more value to the table for a potential recruiter?

Secondly, if I do need to delve deeper into frontend, what should I prioritise first? Backend or Frontend. I don't think I'll be able to do both with equal diligence given how much more vast backend seems.

Thanks for all your responses.