I can really understand what you are going through with interviewing! When I was looking for my first post transplant jobs, I created a spreadsheet to track how many jobs I applied for and how many interviews I had: 146 job applications and 39 interviews. I qualified for all the jobs I applied for. What kept me going was the thought that eventually I will be the best candidate an employer will have and they would be willing to overlook my job history. I hoped that would happen locally, but I finally had to move to be able to work.
Living in a rural area definitely makes your job search challenging. I hope you will be able to find more remote work. I see some employers being more flexible about allowing employees work remotely since COVID forced so many companies to go fully remote. I have one person on my team who moved back from Arizona back home to Oklahoma when COVID hit. She was able to negotiate with her supervisor and continues working remotely now, even after most of the employees came back to work in person.
As far as speaking to my supervisor about my health issues, I really want to keep my health issues private for now. I try not to schedule too many doctors' appointments and do blood work/MRI's before work or on weekends. It's challenging negotiating with my doctors who often want me to get something done within a week and I just have to delay tests and appointments to group them all on the same day. At this point all my conditions are chronic and have to be managed. I will have to speak to my supervisor if I needed a surgery or be hospitalized for a procedure.
I also try to walk every day 1-2 miles. I do it early in the morning before work, plus my parking spot at work is 1/2 mile away from my office, which forces me to walk another mile on the days I have to come in.