Biden had 4 years to make that happen if he wanted, yet at every chance he turned towards economic and political pressure instead of military pressure with Iran. I really do not understand why you think that would have somehow changed in a hypothetical second term.
Trump tried to start a war with Iran in his first term, failed and then forced it in his second term and is failing miserably in every way possible.
It is possible that Biden may have personally wanted to go to war with Iran. I don't know him personally. But every move he made aa President and as VP signaled he did not want to. Regardless of his personal motivations, he probably understood what Trump did not: the US has never had the ability to force the Straight of Hormuz open, Iran has the ability to close it, and the closure would have disastrous economic consequences for the US and its allies.
Its funny you mention Ukraine out of nowhere because the one country which HAS benefitted from all this is Russia. Sure, they supported Iran, but suddenly there are tensions within NATO and the world is more desperate for natural gas.