Putin's former #2 had this to say, and he's absolutely right:
"It’s not clear how the truce between Washington and Tehran will play out. But one thing is certain — Iran has tested its nuclear weapons. It’s called the Strait of Hormuz. Its potential is inexhaustible,” said Dmitri Medvedev, a former president of Russia and deputy chairman of the country’s security council, last week.
Before this, it had been 40 years since Iran tried to close the Strait (during the war with Iraq). They (rightly) feared that closing the Strait would generate a coordinated response from Western powers. But now they've realized they only need a few drones and boats to paralyze tanker traffic. As Medvedev says above, that power may well be more of a deterrent than nuclear weapons ever could be.