I’d recommend you simply follow your curiosity and not take this choice too seriously. If you’re simply doing this for career purposes, then the honest answer is that absolutely no one knows where these fields will go in the next couple years so I wouldn’t take anyone’s advice too seriously.

But as for my 2 cents, knowing machine learning has been valuable to me, but not anywhere near as valuable as knowing software dev. Machine learning problems are much more rare and often don’t have a high return on investment.