The High Fantasy is the setting.
The Urban Fantasy is the setting.
The Portal Fantasy is the hero origin story.
Now you're just making up new rules to support the rules that you, yourself, made up earlier. I already explained how this works: High Fantasy, Urban Fantasy, and Portal Fantasy are subgenres that split off from the overarching Fantasy genre. They are all fantasy, and because of that they may share similarities with each other, but each subgenre is still clearly defined and separated from the others by the basic guidelines that make up those subgenres.
"High" is not a setting, unless you're going to tell me that every single High Fantasy story secretly takes place on top of a mountain. And I know you're not going to tell me that every High Fantasy world is so similar that they can all be adequately summed up under a single word like "high." That would, again, be like saying that Star Wars and Star Trek are the same genre because "space ships."
"Urban" can be a setting, yes, but Urban
Fantasy is specifically a fantasy story that takes place in the real world. Usually in the form of a hidden civilization that exists in secret under normal society's nose, but that's not a hard and fast rule.
Saying that "Portal Fantasy" only exists as an origin story for the hero makes no sense at all. It defines how the hero views and interacts with the world they're in throughout the entire story, which in turn shapes how the story is told and plays out. Someone who was born in that world is going to act and think extremely differently than someone who was thrown into it unexpectedly. If Lord of the Rings was an isekai, it would be entirely unrecognizable as the story that it currently is, and that's why claiming that isekais and high fantasies are the same thing makes no sense.
The Urban Fantasy doesn't operate under the same logic as the High Fantasy. The Urban Fantasy in fact doesn't always include the protagonist being taken or introduced to the hidden magical world, in many cases, they are aware of it from the start. Cases in which aren't aware are, however, similar to the Portal Fantasy.
None of this is relevant to the conversation at all.