Kudos to you!
You have worked hard and come up with some great solutions.
The malls are a really good place to go, and I wish mall management would consider it an opportunity to serve the community and bring people together (and maybe shop too).
Malls that are closed (environmentally controlled) are particularly effective for recovery.
They provide a reasonable air temperature, not necessarily humidity controlled, and safe surface for walking. Parks with clear walking paths are great- but not temperature regulated.

I would still suggest participating in some structured cardiac rehabilitation program for the following benefits: Research validated training; education on how to monitor your response to exercise; guided resistance training, yoga (stretching) and mindfulness for optimum benefit. Hopefully you can get them to start at your progressed level and forward you to greater success. You will gain information and skills to advance yourself!

My qualifier: I am an exercise physiologist and worked in cardiac rehabilitation in the past. My graduate work was "Women with Heart Disease". Back then they didn't think women got CVD. Now we know different. It is an "Equal Opportunity" disease.
Keep up the great work.
Ann Marie