My Black Lab Smells Really Horrible?

I have three dogs and I often know how to fix problems with smells, training, behaviours…etc..but I am stuck on this one. I’ll give you a quick background info on her to understand the situation better.
My lab is 12 years old. She has really bad hips. We take her for small walks, no more than 15 minutes 1 – 2 times a day. This usually causes her some discomfort but she always wants to go and I can’t NOT take her as it breaks both of our hearts. She has chronic ear infections. We clean her ears out 1-2 times a week. We also have a blue liquid we got from the vet which we put in her ear and rub every day. The ears smell horrible and we thought that was the cause, but its not the only one. Her fur smells horrible as well. To the point where when you pet her, I wash my hands after. We also keep her well groomed with a shedding blade and rubber brush to keep her coat nice and light, especially in the warmer weather. It’s almost to the point where we want to shave her to see if it makes a difference, but I’ve been reading up on it and I know it’s not a good idea. So where do I go from here? She’s groomed, cleaned, bathed…and still very smelly. Normal dog smells do not bother me. Even my other dogs can be smelly *I have a cockapoo and cocker spaneil*, but it is never long lasting and never as bad.
Any advice would be welcomed.
Thanks