Your information about Syria is not enough. SDF battled with ISIS and Assad's regime at the same time without any "Iranian specialists" help and it was victorious. Assad had "a large contingent of Iranian specialists" supporting him but had failed in all front until Russia decided to participate directly in the war. That may save his regime for few more years but Assad is just a puppet in Russians hands, just like the puppet government of Afghanistan during the social-imperialism occupation.
You're surprised that the Syrian government was struggling to fend off the CIA and its terrorist proxy armies? Of course they needed Russian help to shift the balance. You cannot expect a power like Syria to contend with the most powerful government in human history all by itself. Yet their resistance to US imperialism was quite robust, given their obvious disadvantages. Many Syrians made the ultimate sacrifice defending secular Syria from the jihadist hordes trying to conquer the country.
Power always thinks it has a great soul, and vast views, beyond the comprehension of the weak. And that it is doing God service when it is violating all His laws.
--John Adams