I think you are doing fine. We have all had the desire to be further along, given that the culture is definitely type A, very athletic here.
That is based on muscular achievement, we are pros at training and pushing the body to achieve in muscle growth and recuperation. HR is a structural procedure that has a large muscular component.
The important part, especially early on is the structural. The first six months are all about getting the bone to heal, to anneal itself to the device that has replaced part of your original bone equipment. Its function is replacing cartilage.
None of that is addressed by the type of training that we're used to or by the techniques that we use in each individual sport or training that we do. The thing that works with bone is to let it heal, then to apply appropriate pressure (by walking, etc.) to promote the bone's healing.
No amount of exercise will help the initial bonding of bone to metal lattice or bone to glue (where used), as a matter of fact, too much pressure early on may put it in peril. Your tool and weapon is that knowledge, that actual bone healing is happening, as well as muscular healing and strengthening.
As time passes, and the bone has healed, then is the time to ramp up the muscular workouts. Patience gets you safely to the point where you can really turn it on and return to your full life.
You are both doing fine, not lagging in any way. Each of us has an individual path back, but common threads.