Trying to define "Personal Computer" is another rabbit-hole, it's such a broad concept. I'd argue someone could be right if they called an iPhone a PC as for many that is their computing device, at the same time as someone else's PC being a monstrous workstation that you'd need to load onto a trolley to move.

On this one, I would say it was quite clear for my generation, a PC ran either an IBM, Digital Research or Microsoft OS and that was it.

That is why those old Mac vs PC ads from Apple were the way they were, back when Apple was relaunching themselves.

Everything else is trying to give new meaning to something that during 1980-2000's was quite clear what it stand for.