The real mistake may have been attempting to pivot to Iran in an attempt to reinstate the JCPOA. As admirable a goal as that is, I also think it’s clear Trump squandered any trust Iran had in the US when he cancelled it. Iran has taken the Biden admin’s overtures as an opportunity to test its regional influence, instead of being a good faith negotiating partner - and why would the Biden admin have expected anything else when the US hadn’t been a good faith partner? Trump was awful on foreign policy, and set middle-east peace back decades, but Biden has completely failed to understand and adapt to the new status quo.
Your quote from the Jordanian commander dates to after the Nakba. There was significant intercommunal conflict in Mandatory Palestine because of the mismanagement of Jewish migration by Britain, and escalating tensions from the “legal” land purchases you mentioned that had been occurring since the late 1800s. Yes, Jews attempted to purchase and settle uninhabited land, but the fact is big chunks of the land purchased were misappropriated under the Ottoman Land Code, and European Jews frequently expelled (by force if the implication wasn’t clear) the Arab Muslims they found living on it, who may have had no idea it was sold out from under them.