Hi,
Can you check if the pi is still connected to the LAN when it dies?
I am having issues with home assistant runnning on ESXi, but this might be related.
my problem: Hassio on esxi losing IP address - HA supervised
Mine just loses its local ip address, however, I can still console to it from ESXi. you can try connecting a monitor to it when it is crashed, check if it is working.