I think your examples are a bit misleading.
I have the indentations correct in my three examples.
A list item continues until
there are _2_ blank lines or until the subsequent line is not indented >=
current list item indentation:
The whole list ends after 2 blank lines. But I didn't demonstrate this rule in my examples. I was just focusing on plain single new line char vs a blank line (2 consecutive newlines) in my examples.
1. list item 1
not a list item because it not indented
2. completely new list
Also,
1. list item 1
Still a list item - new paragraph inside the list
Indented, but not a list item because there are two blank lines above
Everything is described in the manual. See https://orgmode.org/manual/Plain-Lists.html#Plain-Lists
+1