Absolutely right, what you write, and it is often presented exactly like that here and elsewhere. However, I would search the other way around. First the building plot (the land) and then I would plan the house on it. For me, the location is more important than the appearance or type of the house. And a habitable house can actually be built on any plot (in whose surroundings there are single-family houses, that's what we are talking about).
Of course, that does not mean that you *buy* first and then think. You just shouldn’t fixate on one (e.g.) type of town villa and then exclude the dream plot because only bungalows are allowed there (or vice versa).
Yes and no: Whoever wants a bungalow (or everything on one level) tends to need a larger plot. I didn’t mean that you should "restrict" yourself with quasi specifications, but that you should know what you want to build. My experience in searching for building plots shows me that you really have to be able to read (and understand) the development plans well. If, for example, I absolutely want a flat roof, that considerably limits the search.
I share your opinion that location is naturally one of the most important points. That should be undisputed. But then you have to check promptly whether you can and want to operate within the framework of the valid development plan. If yes, all is well; if not, it means keep searching. As soon as there is a reasonable infrastructure on site (doctors, pharmacy, shopping facilities, schools, etc.), it becomes apparent that land prices (as in recent years) will rise.