Syria was home to extensive and utterly useless Russian air defense systems traded for the rent on air and naval bases.
The world learned that all that crap Russia pawned off on Assad was just that, crap.
The cream of the Iranian military leadership in Syria was systematically destroyed by the IAF. Russian troops deployed very recently to the Golan, left as soon as IDF tanks and troops showed up across the border. Russian fighters took to the air but ceased flying when buzzed by the IAF.
In Russia everybody knew that failed, drunk, and otherwise worthless officers, failed in Ukraine, were sent to Syria to hide out and maybe be rehabilitated.
Nice fantasy:)