Iran for decades dont engage in direct conflict. Proxies is their preferred method. The one time they tangled with the US in the late 80s, it was over in a day.
en.m.wikipedia.org
The depressing truth is that, as someone said, Geopolitics are rarely moral affairs. Iran will have to ask themselves if they view Palestinians worth a broader conflict with the Israel and therefore, the US. At the end of the day, Palestinians are not Iranian. So, I'd be shocked if they actually do some shyt. They may get hezbollah involved but the US said yesterday they will no longer treat Iranian proxies as being any different than Iran itself being involved. That may make them think twice even doing that now.