No luck flashing these. They are using a Beken 7231, a pretty detailed thread is here: Unknown Tuya Chip. Looks like they aren’t ESP anymore.
Important note: The item number on my plug is BPPLUG/WIFI/WP/2. The FCC ID is SYM-PLUGWFBTWP
Buyer beware.
It looks like there is plenty of room to pull the MCU off and swap to ESP… but I don’t know if I have the drive to do that.
I’m thinking my next option is to use my pfSense firewall to quarantine these devices so they can’t see any other devices on the LAN and just use the tuya component in HA