This is a damn good idea. Closer to the equator means less fuel energy needed to make equatorial orbits. Russia only has a single model of heavy-lift rocket right now, the new Roscosmos Angara A5. It works but it's an open secret at this point that it's ridiculously expensive to fly. It's basically SLS with Roscosmos characteristics. The Russian comms company Gonets Satcom got roped into a few early flights coming up, but as far as I can tell, all future planned Angara A5 flights are in-house Roscosmos projects. The only flights Roscosmos is apparently able to sell to foreign customers are on much cheaper rockets like Soyuz.

And building a launch site outside Russia's borders is a project with solid precedent. Russia and the ESA did collaborate on Soyuz launches at the Guiana launch site because all the extra effort was worth it for the added payload capacity. I have no doubt Roscosmos could competently build a new Soyuz launch facility if they could afford it. Soyuz has the added bonus of not needing exotic propellants. It runs on plain old RP-1 fuel. The upper stages run on hypergolics but not in any huge quantities that would be difficult to ship in.