One of the questions that pops up regularly regarding voice over work is should a voice over talent pick a few niches and market that, or should you go for many "slices" of the voice over pie and sell that?
I'm a firm believer in becoming very proficient in several genres of voice over but staying away from trying to be a jack of all trades. You can make a good living specializing. A lot of times, as your career progresses, you can see trends in what type of VO work you're being hired for. Mine tends to be corporate narration and e Learning. Sure, I'll record radio or TV scripts from time to time, but corporate and learning is in my wheelhouse.
I sometimes say that voice over work is like a big rainbow. You have audio book narrations, radio and TV commercials, documentary, explainer videos, e Learning, business videos, on hold messaging, product promos, animation and on and on. Become very good at several pieces of the "rainbow" and market that to producers and creatives.
Certainly, be open to expanding and trying new things. But continue to play to your strengths and focus on what you enjoy recording, as well as what you do best.
The great, late "In a World..." superstar Don LaFontaine made millions voicing primarily movie trailers. But I highly doubt you'd hear him on an on hold message or Power Point presentation. He knew which side his bread was buttered on. Not to mention the huge pay difference.