Stuck on if niching down will actually help me or hurt me early on in my career…

I see it very often at this point, that the key to building your caseload is niching down, but 1) How do I even know what niche feels best for me this early on if I don’t have much experience with different varieties, and 2) How does that not just limit me from being able to work with broader clients? Is it more of a thing where it’s about super longterm payoff more than faster caseload building? I would really love to hear some of your niches and how they’re working for you!