The sefer Vayoel Moshe will answer all the above questions.
Just because something is not mentioned in the Shulchan Aruch doesn’t mean that it’s not a real Halacha. The laws of lashon hara are not enumerated in the Shulchan Aruch. So lashon hara isn’t a real sin?
Even if it is only a “medrash” and not a real “Halacha,” it still reflects the ratzon Hashem – and the ratzon Hashem is that we should not have a Zionist state while we are in golus.
The vast majority of gedolim were either anti-Zionist or non-Zionist (Chofetz Chaim, Brisker Rav, Satmar Rebbe, Chazon Ish,….)