Saudi Arabia. Russia supports Assad and has no interest in destabilizing the country because they want to maintain their naval base at Latakia etc.
Really? I did not know that. Have you a source?
> The Turkey-backed FSA's wages are paid for by the Turkish government, they operate alongside the Turkish Armed Forces
https://en.m.wikipedia.org/wiki/Syrian_National_Army
As for their terrorist proclivities:. https://foreignpolicy.com/2019/10/14/turkish-backed-forces-f...
To be fair though, they basically took over the CIA operations.