I think the only qualified people to advise you, should be your cardiac team, RR Only your clinicians know your medical history and should advise an appropriate way forward.
I have had two heart attacks and had cardiac rehab. Is that not happening at the moment, due to Covid? That input is invaluable.
My heart condition is unusual, no blocked arteries, leaky valves, poor diet etc etc, it has been caused by my RA affecting my heart. However, I am still taking steps to maintain a healthy lifestyle.
Not exercising, will compound your condition, however, you need professional advice.
COPD and RA means that my exercise routine has been adapted by a cardiac phsiotherapist, but walking and keeping my steps up, is something I aim for on a daily basis. Circumstances often get in the way, but I do try.
In addition, I wear a smart watch to keep track of my steps, oxygen levels, heart rate etc.
When I had my latest heart attack in the middle of the pandemic, I was able to tell the call handler, my BP, heart rate and oxygen levels. An ambulance was dispatched immediately.
The first thing you will be advised in the event of a suspected heart attack is to chew dispersible aspirin. The handler will tell you the correct dose. Have some to hand. It could save your life!
Good luck with your new lifestyle and keep well!