Recommended OS

[Zdrobot]

Hello!
Could somebody recommend a OS for ESP32 for IoT development?
There seem to be so many out there - TinyOS, RIOT, Contiki, Mantis OS, Nano RK, LiteOS, Apache Mynewt, Zephyr OS, Mongoose OS, FreeRTOS...
More specifically, I need Bluetooth Mesh support, but having other functionality (e.g. WiFi, which seems to be wonky in Zephyr OS for example) is very desirable.

In other words, is there an OS that treats ESP32 as a first-class citizen, not an afterthought?

[ESP_Sprite]

ESP-IDF (based on FreeRTOS) is the SDK we recommend, as we're actively developing it and the ESP series is it's main target.