So it looks like being hidden is only broken by making noise, being found by an enemy (which seems to be defined as perception beating the hide check), attacking, or casting a spell.
So the invisible condition is a mechanical condition and does not mention being transparent. It is like a 4e condition, essentially some mechanics that can be reskinned and applied to different situations like when you are hiding and not seen but are not transparent.
So the big question is once you are hidden and have the invisible condition what happens when you come out of the cover you needed to establish the invisible condition.
A DM could rule that finding is as RAW defined in the hide action itself, a perception check to find the hidden person.
A more narrative interpretation could be that stepping out means anyone can find you and that the perception check is just one way to find you even in your concealment. A DM can also lean on the first sentence of the hide action to say that hide means you are concealed where you hid and leaving the concealment is leaving the concealment.
The specific conditions for breaking the hide invisible condition though and the mechanical non invisible invisibility condition is a decent argument for non-magical distraction and not being observed or noticed as you move until you attack or make a noise.
In D&D on a grid there is no facing, you sort of see 360 degrees around you and you sort of don't, it is a bit abstract and leaves narrative room for walking straight up to someone unnoticed to get advantage on an initial attack.
So like in 14 it is up to an individual DM interpretation.
