u/BirdOk5494

I have a 9 year old cat, that doesn't like to play that much. Since I moved to this house he meows a lot and seems bored. I let him roam around the house, he has toys and boxes everywhere and a vertical space in my bedroom. He also has access to the balcony and I go on walks with him.

The problem is I am really worried because he overeats and sleeps a lot and I'm sure it's out of boredom.
And I can't adopt another cat to keep him company because he hates other cats (I've tried adopting before and I had to re-home the other cat after one year trying).

Is there anything else I can do that isn't crazy expensive?