Put it on the resume as a line item
Format it like any other entry: Career break, 2022–2024, full-time caregiving. That is the whole thing. No apology, no elaboration, no defensive framing.
You are not obliged to give a reason at all, but a stated one is far more reassuring than silence.
Do not use a functional resume
Functional resumes that omit dates are read as concealment by recruiters and parse badly through applicant tracking systems. They draw more attention to the gap than the gap does.
Show currency instead
The only legitimate concern behind the question is whether your skills are current. Address that directly: a recent certification, a course, freelance work, or volunteering that used professional skills.
Two or three concrete items are enough to answer it entirely.
In the interview
Answer in two sentences and redirect, then stop talking. Over-explaining signals that you think it is a bigger problem than they do.