Hi, friend!
He also became interested in the Home Assistant system, but was upset by the lack of support OTA.
I use a system Majordomo for MySensors devices and my Ethernet-RS485 gateways are based on ENC28J60.
And I found such an idea for myself - to implement a proxy for the TCP protocol in order to implement a parallel connection to the gateway of two systems at the same time.
I tested this solution and it turned out to work - I was able to flash via OTA , while simultaneously receiving data in Home Assistant.
Perhaps this idea will be of interest to you.
I have encountered the same situation trying to use a switch to control some blinds.
Has there been any update on this issue from either Home Assistant or MySensors, or any workaround developed?