I just saw that Metahuman SDK audio file lipsync using a Russian cloud server but am unsure about it, I don’t tend to go to sites in that country, not saying unsafe, I do use Duckduckgo sometimes after all and some 3D assets made there but not quite the same.
I am wary of anything cloud based anywhere TBH.
https://www.unrealengine.com/marketplace/en-US/product/digital-avatar-service-link