There is a ESP-NOW based mesh network library https://github.com/aZholtikov/ZHNetwork developed by Alexey Zholtikov.
I have tested it and it works really great. I was able to get ~200m range non LOS (in my farm).
Experts and developers please can you look in to this?
It will be a great alternative to nrf24 as a $2 esp8266 has all the hardware built into it (mcu, radio, storage, encryption chip etc). It ill be a great hardware for simple diy hardware.
I have asked the developer to look into mysensors code https://github.com/aZholtikov/ZHNetwork/issues/1#issue-1628821616.