Being in tech has the advantage of me being knowledgeable enough to pursue tools and languages of interest that will benefit both my business and day job.

That is what I did. I learned web development and used those skills to do projects at work and for my clients on weekends.

Later on, I learned project management. Used those skills at my day job and made a consultancy killing as a PM for hire.

I feel privleged to have been in this position. So, yes, I do advocate for spending time increasing your value at work. But that time should also work for you outside of that day job.