The blog post is a "nothing to see here". You really fell for it? Do we still do car analogies? Here's this car with just a ignition button without keys, and keys to your home in the glovebox and the address already on the GPS... but the thief would have to break into the car first!
If you can break into the application running on an ESP32, you already have full access to RAM etc. The debug HCI commands will not give you any extra access.
Yes, security researchers are incentivized to make issues seem like more of a problem than they are, and vendors are incentivized to minimize them. In this case, though, the reality is much closer to Espressif's version.
* as we assumed with sbcs like raspberypi earlier...
This analogy makes no sense at all. Once you break into a car, you can quite literally do anything to it. The keys to your home part is simply random.