OP in the referenced post stated that version 2.1.35 had no issues with addons, I found this to be the same. I was able to install both addons in that version and reinstall latest and the “Set Font Size” addon is working. However, “Review Heatmap” requires version <= 2.1.48 so that is the version I am running.
To be clear, the CA cert was present under c:\program files\anki\lib\certifi\
If you have any further steps to resolve the issue in 2.1.60 I would be happy to try, even at the expense of Heatmap (the UI is nicer…)