I’ve researched the code and it seems like the OverrideInvisibleLevels should technically work only on streaming levels (aka blueprint loaded). In your case, you may want to use Load Streaming Level instead of Load Level Instance (by Name). There is an issue in networked sessions as well, when loading the level instance by name. I think they are fixed and not streamed, therefore not working with the PCVO system in-general.
I would prefer it to work on regular/static levels, and be instantly visible in-editor (like override invisible actors currently does). It must be that the entire level is hidden, not the individual actors. If Epic could develop a function of “Get all actors in sublevel” then that would allow users to create their own versions, as well. Right now I’m creating a hacked version of this using actor tags. @EpicGamesSupport