@OldSurferDude well, the ESP8266 is limited to 4 TCP clients in arduino IDE. This can't be really increased. I did som experiments and you can set it up to 15, but after the 5th client on my web server, I got a freeze.
Maybe you got something wrong. #define MY_GATEWAY_MAX_CLIENTS 2 defines how many controllers (eg Home Assistant) can connect to the gateway, not how many sensors/MySensors devices.
And yes, you can have multiple TCP gateways in HomeAssistant. I got an NRF24, an RFM95 long range and a RFM95 short range gateway (all based on ESP32) on the same Home Assistant.
Regards, Edi