my senior dog is really depressed

i dont know if she's senior senior but she's 9 years old.

my family is not a dog family, or its not a good environment for a dog. we're all too busy to tend to her needs as a staffee but we certainly try our best. my sister frequently buys her toys but we dont ever play with her.

we take her walks about five times a week, we try to do it every day but things get the way.

we feed her well and we listen to her when she wants something and i sometimes just sit with her and pet her because shes really lonely and sad

as i said, we're not a dog family (we used to be when i was younger) so we cant get a second dog. we did get these rescue kittens earlier this year and my dog was super happy with that for a while and it taught her a lot about body language and other animals. she loves them but they only play with each other, not my large dog.

last night while i was working on an essay, she was in her bed just quietly whining. i stopped so i could give her some pets but its recurring.

what can i do? or what can we (my family) do to cheer her up and keep her living, not just existing.