More droids. Until they make too many, than Dooku has explosives installed throughout the structure, justifying it as a self-destructive protection Incase Republicans get their hold on it.

Of course, Republic Intelligence somehow 😏learns of this and the Republic launch an attack and successfully destroy the Star Forge.

Well it kinda depends doesn’t it? Would Dooku with such a weapon continue to follow Palpatine’s plans or strike out on his own?

Remember that the Star Forge was a Dark Side nexus which corrupted those who spend to much time inside as not Force sensitive and driven more towards uncontrolled emotions like rage and increase the desire for power as Force user. 

Even without a Star Forge CIS had the largest military in existance ever. Star Forge itself was an automated shipyard unlike its cousin the Foundry which was a dedicated automated droid factory. Only reason I can see it play out in your scenario is if those multiple Forges must not be a Force-Operated like all the Rakata technology and even then I doubt that Dooku or CIS would need it anyway. Assuming also if it was hidden in known space because delivering military gear accross half the galaxy out of the deeps of the Unknown Regions is sketchy at best and Republic would pick up on that even if Palps wasn’t involved.

A lot of paperwork and energy bills.

Also, the Republic would have already found a Star Forge several millennia prior. Don’t know what would have become of it since the Sith Empire took it over and “killed” Revan, but they should have knowledge of it.

Dooku might just keep it secret, between him and Palpatine and the few dead bodies who found it, and save it for the Empire