What pays the most?

You'll get paid as per the product/skills you can deliver

ML/DS but have at least a Master's degree if you don't want to struggle later on in life.

The Amazon Applied Scientist role can get you 40-50L per year. The interviews are equally tough.
You gotta be the cream here.

Backend engineering has a HUGE demand, and is short in supply of 'good' engineers.
Easy to excel here for the average bloke.

As a front-end dev looking to move to a higher pay, should I move to full stack? Does that make sense

Finance