Latest updates in HA Add-on rewrites Serial Number to 007 for some reason.
All you need to do is stop the add-on. Edit configuration and change your serial number back to the correct value...remember to SAVE (button is right at the bottom so not that obvious) then start it again.
Industrial 1-Channel ESP32-S3 WiFi Relay Module, Supports WiFi / Bluetooth / RS485 Control, With Multiple Isolation Protection Circuits, Industrial-Grade, Rail-Mount Case | ESP32-S3-Relay-1CH
www.waveshare.com
Was actually in the middle of doing a full diy with an ESP32 dev board and TTL-RS485 converter before finding this but decided to try it out rather since it is more discrete.
So far so good but will have to see how things go since there were some on here who did do the esp32 route and said their rs485 boards stopped working.