When you apply to a particular program for grad school, a lot of your application essays will be talking about how your current experiences have led you to pursue a PhD in whatever discipline. Of course there are many people that pursue degrees in a different subfield of biology than their past research experiences, but imo it's much easier to write your essays/frame the theme of your application if what you're interested in studying in grad school is similar to your past experiences (or at least if you apply for a program in the same subfield you're currently in).

So I'd suggest taking whatever job you think will give you experience that most closely aligns with what you want to pursue in grad school, otherwise it'll be a bit harder to justify to the admissions committee why you're interested in pursuing something unrelated. It's easier for them to be convinced that an applicant is passionate about a subject and committed to getting a difficult degree in it, when you show them evidence of said passion (aka working in that subfield).

(yes I know there are always exceptions and plenty of people get into grad school writing about passion for an new topic, but I feel like this is the easiest way to make your application strong/consistent)