COPD supplement and rehab

I am new to this site. I was diagnosed with COPD over 20 years ago. My first symptom was shortness of breath while speaking. I was diagnosed with moderate mid- airway disease and the diagnosis never changed. I use a steroid inhaler, albuterol is needed, singular, sinus rinse. I recently rediscovered cordyceps mushrooms and I take a thousand milligrams per day in a capsule. I really feel that it helps my lungs to expand. I'm also looking into pulmonary rehab. I'm looking at the PEP and IMT (Power Breathe) devices. My pulmonary specialist doesn't seem to know much about these devices, but I got a lot of information from AI. I asked about pulmonary Rehabilitation and I was told that there's more than a year-long waiting list. So I think I'm going to go ahead and start these devices on my own. Does anyone have knowledge about these devices? I've read a lot about them and they seem reasonable and like they should help. I don't think they can hurt you. The only caution is, if you have a lot of mucus use the PIP first and then the IMT so that you're not pushing mucus into your lungs. I'll post further after I try them out. Thanks