Nothing is erased. Ignore the home-assistant.log files in /config, they are irrelevant. That’s just a file where core replicates logs since the last restart for convenience.
Your real log on a system with supervisor is the system journal. It contains everything from all containers and system itself and is persistent across many restarts
I wrote a guide on how to access it. Take a look and start there, hopefully that can give you some insight into what’s going on.