During your sabbatical you can’t just stop everything. Take the time to learn about the technology you want to work in. Build something you want to build.
I say this as a 35 year old IT professional “between jobs” building a platform in the tech stack of my choosing for the job I want to return to. To be honest, my goal is to never return to “full time employment” but to build enough revenue to continue this “retirement” lifestyle.
You don’t stop working in retirement, you just work on things you find pleasure in and for me that just happens to be building the things I want to build when I want to build them.
I’ve taken a couple of these sabbaticals in my life, already, and would recommend them to everyone. Of course it requires preparation, but every time I return to the work force, I have increased my knowledge and as a result my pay. I earn 4–5 times what I did a decade ago, all without a college education and no debt.