Better to learn ElasticSearch, or Apache Spark & Kafka, for career growth?

Hi all.

My suggestion is exactly what the title asks, but I wanted to provide more context before you suggest.

TL;DR at the bottom

This is my first job after college. I've been with my current company for 2 years.

Before this, in college, most of my projects used to be related to data science (Deep Learning applied in Computer Vision, and Natural Language Processing as well). These weren't my course projects, mostly for international competitions, and published two research papers as well.

However seeing the scope of data science in this country three years back- and uncertainty of covid, I opted to learn development and learnt more on the backend of web development - my last internship before college ended was a company that utilised SpringBoot and MongoDB, so I was comfortable with Java as well.

I currently work in an organisation as a support role primarily. I've been working closely with Kafka and ElasticSearch for about 1-1.5 years, without actually learning anything much about it apart from mindelesly running commands that are told to me. My main area of expertise lies in the overall architecture of the software and functioning rather than these two aspects, and the business end.

I have recently been wanting to upgrade my skills (my support role has made me rusty and lazy, hence took me so much time to realise it), and I was wondering which one would be a better fit for my profile.

Current aim is nothing except:

1. Earning more money
2. Trying to land potential jobs outside this country, to gain experience.

Based on these requirements, what would be a better technology to start off with?

Online searches aren't helpful, and most of my friends are not working in either of these stacks, so not sure what to do.

My manager told me that ELK stack is a newer technology that is the 'hot' thing in the market, but I've heard of Apache Spark & Kafka and their utilisation in the Hadoop ecosystem.

Certifications for both are available, provided by the company. (These are 3rd party certifications so are valid even if I leave the org- albeit after a certai period. I am ok with this).

Any help or insights from experienced people would be helpful as to which tool to pursue, based on my previous experience on resume.

TL;DR- Wanting to upgrade skills for higher paying job, or potential outside country jobs. Which technology would be better to learn? ElasticSearch (ELK stack) or Apache Spark & Kafka? Previous experience in Deep Learning model developments, REST API development, implementation of MVC architecture.