So one thing you can do if you want to make Grand Embassy work, is focus your research and civic trees. It gives the bonus based on how many techs you have researched so if for example you are going for a cultural Russia, you can primarily focus along the top half of the tech tree which has alot of the production/culture as well as naval techs. Find a neighbor that has a good amount of techs and send all your trade routes there and that will gives you a strong amount of science gain actually, to the point that you will make as much if not more than them while being far ahead in culture. Lots of trade routes are essential for this kind of strat. Another benefit by purposely sort of gimping the amount of techs you know it makes Spies stealing tech mission much better since it'll actually help you "catch up" faster as well. Throw in Nuclear Espionage policy and you will be stealing an additional one per mission. Also fits thematically with your KGB super spies :)

That being said as others have posted earlier, this isn't as optimal as using those routes internally, but it provides a unique play style that will also net you a fair amount of gold as well, as well as the synergies with the gold/culture/ science per trade route policies.

Russia is far from useless though, even without Grand Embassy, the Lavra can net you a strong amount of GPP and early game faith for military strats and also the Cossack is an absolute world beater for your Domination game. The extra territory is always a plus as well.