Separate Dog and Cat? Who to separate?

My dog is 4.5yo Great Pyr. Had him since he was a pup.

Cat is a standard issue cat. She’s 1 now. Got her at 12 weeks last year.

They were separated for the first few months basically at all times. My dog never really shows any interest in her unless she’s getting zoomies and is moving a mile a minute then he perks up.

I’ve been leaving them out in the house together for the last few months and I’m starting to think maybe it’s a better idea to keep the separate when I leave the house. Mainly due to the size difference.

They don’t interact from what I can see in the cameras. But at the same time my dog is starting to become a grumpy old man. Aka doesn’t like when other animals disturb him while he’s sleeping or minding his own business. He will grumble. The kitty will immediately move away when he does that if she’s been in his face bothering him.

I think all around it’s probably safer for me to separate them. But who to separate? My dog tends to prefer my bedroom if I am gone so closing him into there is a simple enough move. And all he does is sleep while I’m Gomez Otherwise the kitty has her own room upstairs with her cat tree BUT I would have to place a litter box in that room (litter box is currently in the basement).

Should I confine the dog to one room? Or the cat? Thoughts?