As a principle we should avoid buying any weapons from Russia as long as Putin is around due to their stance in Syria. Or well-known and decade old crimes in occupied Caucasus. That's just me talking and I know that such opinions don't matter the slighest when it comes to geopolitics. I have nothing against Russia or Russians but I can't support Russian policies in Syria or what they have been doing in Caucasus for generations.
Anyway there are better alternatives such as the West.
What's better there is China and Ukraine.
I believe that KSA will definitely go for the Grom-2 missile system that we are rumored to help finance. This would fit well into the current policy and make sense given other military ventures (Antonov) etc.
Ukraine is also willing to do JV's and TOT.
Unless Russia, out of the sudden, is willing to offer JV's and TOT and in general increase military ties with KSA. That is very doubtful.
Rather focus on China and Ukraine first and foremost when it comes to partners and also Turkey.