Sadly, I don’t let my Zeus on the bed anymore. Once he snapped at my husband when he was told to hop down. He had been up keeping me company (which I didn’t let him do often)and didn’t act appropriately when told he had to leave - we were floored by the snapping. Never allowed on the bed since.
He used to start out in a little ball at the bottom of the bed, and gradually would magically expand until he was lying stretched full length up the middle of the bed, and I would be shoved to the edge. I always felt perfectly safe.
If you want him back on the bed, here’s how you fix that.
Tell him to come up and let him lie down for a bit.
Then, for no apparent reason, calmly but emphatically tell him to get down.
Lather, rinse, repeat, a lot.
If you persist with that simple training, he will eventually get the point that you can and will capriciously assert your rank for no reason other than that you *can* and will accept his role as subordinate.
He is seeing himself as pack leader [even if that’s his only “symptom”] and no dog is truly happy leading the pack.
If you do the above, it will actually assist him in becoming a calmer, more emotionally balanced dog.
You will ‘relieve him of his command’ which is, to a dog, an awfully heavy burden.
When Odin hit puberty, he had a similar issue with my sofa.
Now he just sighs and hops on or off when told to, simply because I said so.
If you haven’t already, try and get his thyroid checked.
Our breed is infamous for hypothyroidism which usually manifests as ‘snarkiness’.