I was just at Best Friends Animal Sanctuary (largest no-kill sanctuary in the US!) and volunteered for a day. I spent the morning at Old Town with their senior and special needs dogs. Some of the dogs had mobility issues that meant they were slow walkers, or could only do short distances. They all seemed happy to hang out with each other, scarf their food, and get outside for a bit. One dog had some sort of injury where she couldn't use her back legs at all. They loaded her into a little wagon with wood sides (like you see parents put their toddlers in to go to the zoo) and took her out on a walk just like the other dogs for some fresh air and routine. It honestly almost made me cry to see this dog go for a ride in the wagon, being walked by a young volunteer pulling the wagon, flanked by an elderly widower volunteer with a bad leg of his own.
I think if an animal isn't clearly in pain, it's worth offering whatever help we can to make their lives as happy and healthy as possible. You might be able to entertain your dog on bedrest with some new toys that don't require fetching (thinking of Kongs with peanut butter, ice blocks with a toy or treat inside) or do frequent groomings, more car rides, wagon walks, possible dog play dates limited to a small room, sitting on the floor with the dog while you watch TV/read/scrap so they get some attention, etc. Best of luck!