I am not sure how useful Gwadar is for Russia despite hearing about the news of warm water one of the key cause for Russia's intervention into Afghanistan.
Russia is too far from Pakistan and there are only few states of Russia which can really benefit from Gwadar. They are welcome to invest in Pakistan and be part of CPEC however the trade route of CPEC is economically not viable for Russia. They would have imported oil from middle east but they already have it in abundance so what exactly are they going to transport from Gwadar... not very much if nothing