I was saying that I don't know what a particle is, and neither does anyone else, but subjective isn't quite the correct word.
What I am sayings is that there are many useful interpretations of what a particle "is" that allows science to progress. The theoreticians and the experimentalists use, sometimes even form, those interpretations to help them along in their work. I'm saying that they yet remain interpretations, even analogies; and it really doesn't matter whether those folks believe in an objective reality or not, good work still gets done. Maybe it's subjective in that sense, but a particle is whatever they say it is; and nothing more can be said with certainty unless you dive into philosophy.
You can measure a perturbation in a field, or a track in a bubble chamber, and call it a particle. Then you can work backwards to an "objective" representation, and a particle still becomes whatever you say it is. It's still scientific, consistent, mathematically rigorous, and in line with theory and observation, but it remains a human construct. You can't escape that. Ultimately, one is free to believe that there is some fundamental thing; and, maybe there is and maybe there isn't.
> literally everything we know of is whatever we say it is
Of course "literally everything we know of is whatever we say it is". That, precisely, is my point. It most certainly does not mean that we can just state anything as true unless it is sensible, consistent, observable and verifiable; and expect not to be challenged.