Advanced weapons include precise missiles, surface to air missiles and air defenses transported mostly via Damascus airport which has come under repeated strikes attributed to Israel
As the U.S. was supplying Israel with military aid, so is Iran delivering weapons to its regional allies, in transports through the Damascus airport mostly, while other weapons transports arrive through other locations.
The frequent strikes on Syria in recent days, attributed to Israel, were for the most part intended to thwart such transfers from Iran, that were meant to increase the number of precise missiles, anti-tank missiles and air defenses including the Iranian made surface to air 358 missiles also called SA-67) that can intercept drones, planes low flying aircraft and missiles, available to Hezbollah.
Iran had already supplied its Lebanese proxy with a substantial stock of missiles which have been used by Hezbollah against Israeli drones recently but have thus far failed to shoot any down. Israel has been able to intercept the 358 missiles using its air defenses.
Here is how it goes with US president.
One make it easy for Iran to build their nuclear power. The next butcher the deals - accelerate nuclear progress. The next says will, the last president fucked up but now we have to go to war.
It is the same cycle for many different things. The only people who benefit from this in the middle east are weapons manufacturers and Isreal.
Since Biden took office they been blaming Iran more frequently than usual which to me seems to indicate an attempt at justification for an attack.