The reason the frum community in Eretz Yisroel doesn’t elect to gain (on the books) employment is because the Zionists passed laws making it illegal for frum people in Eretz Yisroel to work unless they first join the Zionist Army. And the frum will not join the army since the IDF will shmad them into Israeli goyim.
If they would me allowed to legally work without enlisting in the Israeli army, you’d see them working legally. But the frei don’t let the frum work.