Argyle King
Legend
The Invisible condition is the correct approach, and simplifies many variables.
Probably it is the Hide action and the Invisibility spell that need to clarify how one maintains the condition.
I still think (as I said earlier in the thread) that the simplest solution would have been to include a "Hidden" condition.
It could function similar to Invisible but it would also be a lesser version and have other criteria for how it is gained or lost.
It would have overlap with Invisible, like how grappled and restrained have some overlap but are two different conditions.
Taking extra time for clearer writing upfront saves a lot of work to spell out various conditions and exception-based design later.