Should I communicate in my applications that I'm unemployed out of choice rather than because nobody will have me?

Today in a call a recruiter mentioned that I might want to consider finding something fast because having this few months out of employment "raises some questions"

No it does not.

A "gap" only raises questions if it's a gap. If you worked from 2011-2016 and 2018-2019 and refuse to tell me what you did in between, that is a gap. It probably means a prison sentence, rehab or anything else a person would like to hide.

However finishing school and then touring the world because you will never be that independent and free again is not a gap. It's not secret. It's actually remarkably realistic.

So whatever you want to do, do it. And tell. I don't mind seeing a CV with 6 months of travelling Australia or something. Do it now, so you don't have to regret not doing it, or somehow trying to do it while working for me.

However, be prepared to tell. If you cannot tell or have nothing interesting to tell, people will think you hide something. So for example travelling Australia is great. Telling me you binge-watched Netflix specials for 6 months because your mom paid the rent and food and you could is not impressive.

So it boils down to: do interesting stuff that you can put on your CV, even if only as a single headline ("2019 - Toured Australia and South America") to explain a perceived gap. Or get a job. But you certainly don't need a job as an excuse if you have interesting stuff to do instead.

^{Disclaimer: "Australia" from my point of view is the other side of the planet. If by any chance you are from Australia, maybe pick another target to "see the world".}