This is a widespread fear that personal trainers have.
I've helped a lot of clients realise that by choosing a niche, they aren't limiting themselves and that they are strategically setting themselves up for success.
I struggled with this idea of niching down in my own business.
I spent years talking about "sustainable training" (what does that even mean?) or trying to market my online personal training business with general holistic health and fitness advice.
During this time, client attraction was slow.