Sure but if my PC is hiding from your creature and I ask which direction you are facing so I can decide if you can see me then you would have to declare which way you are facing. You would still have a LOS, just not be looking down it, so not facing me.
Actually this is part of the problem with the Hide action in 2024 and I posted upthread (or maybe in another thread...?) about it and why I am here discussing it.
Hide
With the Hide action, you try to conceal yourself. To do so, you must succeed on a DC 15 Dexterity (Stealth) check while you’re Heavily Obscured or behind Three-Quarters Cover or Total Cover, and you must be out of any enemy’s line of sight; if you can see a creature, you can discern whether it can see you.
On a successful check, you have the Invisible condition. Make note of your check’s total, which is the DC for a creature to find you with a Wisdom (Perception) check.
The condition ends on you immediately after any of the following occurs: you make a sound louder than a whisper, an enemy finds you, you make an attack roll, or you cast a spell with a Verbal component
If you can see a creature, you can discern whether it can see you? Bullsht!t.
Even IRL just because something happens to be looking in your direction doesn't mean it sees you. It might, sure, but even if it does you can't possible
know that. You might suspect it, but that's it.
Now, let's examine the actual rule:
You must be out of an enemy's line of sight. This means the enemy's line of sight must be obstructed. Well, this isn't a problem if you are Heavily Obscured or behind Total Cover in most cases. There are outliers and expections, like with a
wall of force (which is invisible but don't even get me started again on THAT!). Three-Quarters Cover does not block line of sight. So, right there you already have an impossibility and I would love for someone to explain
that. But, moving on...
So, ignoring the Three-Quarter Cover issue, Heavily Obscured and Total Cover break line of sight... but this works both ways with Total Cover! That means YOU can't see THEM, either!!! And really, since you can't be seen, any Dexterity (Stealth) check you make is really to be quiet.
Heavily Obscured is a different issue. You are Heavily Obscured, not them. So, you can see them, but because you are Heavily Obscured they are considered to have the Blinded condition while trying to see you... Wait a minute! That means they
automatically can't see you... so again, since you can't be seen, any Dexterity (Stealth) check you make is really to be quiet.
So, what this boils down to is this:
With Three-Quarters Cover, they have Line of Sight and can see you, and you can see them--so no Hide action.
With Total Cover (barring edge cases), neither of you have Line of Sight on the other, so you are just trying to be quiet, not "hide".
With Heavy Obscurement, same as Total Cover...
As soon as you move from behind cover or out of heavy obscurement, you are seen due to Line of Sight being established, and lose most of the benefits from the Invisible condition.
What the heck is the point of this!?!
Simple. It is badly written and the lack of facing rules is the key problem. The DM (as always) has to decide when you can attempt to Hide (i.e. the enemy is NOT facing you--as you say--and cannot see you). But here's the rub:
If the enemy cannot see you due to "facing" away, why do you need cover or heavy obscurement in these cases? You are
already unseen!
Frankly, it is a hot mess IMO, and any attempts to Hide are really attemps to move quietly so they don't HEAR YOU! Crazy...