I'm an experienced professional software developer. In my day job, I use all sorts of fancy tools. Nonetheless, when I returned to fiddling with electronics a few years ago, my journey with microprocessors was typical for hobbyists.

I started with an actual Arduino and the Arduino IDE. That tool and the ecosystem definitely fulfill the mission of making it very easy for beginners to ... begin. It doesn't take long for experienced software developers to get frustrated with the IDE. I'm not complaining about that since I empathize with the IDE's goals. (I also tried the beta of Arduino IDE 2.x and found it kind of a puzzle. I tried it fairly early on, and it was plenty buggy and slow, which I forgive on account of it being an early beta. The puzzle is ... what's the point? If you've outgrown the original Arduino IDE, why not just switch to some other free or commercial IDE that groks the Arduino ecosystem? Well, it's not up to me to tell someone else how to spend their time.)

When I moved along to ESP8266 and ESP32 boards, I continued to code for them using Arduino tools. The board definition stuff that the Arduino project or Espressif or somebody provided is really handy for exploiting the vast collection of Arduino-compatible libraries. You still end up with the setup()/loop() model of an Arduino "sketch", but within that there is lots of library help to do a lot of things.

I've been using Eclipse IDE for Java development for many years. Although Eclipse is most mature as an environment for Java development, it also has plugins to support other languages and various frameworks. For example, PHP and C/C++. In my experience, these vary quite a bit in maturity and features, but at least the Eclipse IDE aspects are familiar. I explored some customized Eclipse environments for Arduino development. They were serviceable, but my recollection is that they felt like works in progress. Some of them have faded away into staleness by now.

I've done a few projects using ESPHome, for example, my Water Watcher project. The idea of ESPHome is to mostly eliminate coding to wire up devices to ESP8266/ESP32 boards. An ESPHome "source" file is a YAML file where you list the sensors you have, their pinouts, and other configuration details. The framework then takes that, generates the C++ code, and then compiles that into firmware for the board. There is still a loop, but it's mostly hidden from you. You can tell it things like "read this temperature sensor every 5 minutes", and ESPHome makes it happen. It's a very nice environment. ESPHome has an "escape" mechanism where you can do custom things in C/C++. Although powerful, it's a bit clumsy to do more than a few lines (mostly I blame the clumsiness on YAML constraints).

But enough about that. I spent some time thinking about whether I could use those environments for this project. It might be possible. I have the intuition that I might have to get pretty deep into the Bluetooth stack in the ESP32 for this project, and I didn't want to get into a lot of bother fighting with my environment. I already know that fairly precise timing can matter a lot for some stages of Bluetooth protocol, and I was afraid of being stymied at some point by the inherent loop structure of Arduino sketches or ESPHome. It is possible to dive down deep in either of those frameworks, but I didn't want to be fighting the framework all the time.

Espressif publishes the Espressif IoT Development Framework (ESP-IDF). I'd been seeing references to it here and there for quite a while and was interested in checking it out "someday". I had somehow gotten the mistaken impression that ESP-IDF was an IDE, and I wasn't anxious to devote a lot of time to learning a new IDE for a hobby  project. I'm glad I was wrong about that. ESP-IDF is not an IDE; it's APIs, libraries, and some tooling for developing C/C++ applications for the Espressif processors. Not only is it not an IDE, but Espressif provides plugins for both Eclipse and VSCode IDEs. The documentation for ESP-IDF is very good. Setting it up on top of Eclipse CDT was pretty straightforward. I did have to work my way through some puzzlers in the first few days, but no more so than early use of any sophisticated tooling. There is lots of forum help for finding answers to common problems. My only complaint, which is minor, is that the documentation sometimes points to sample code that has not kept up with the evolution of ESP-IDF, so it sometimes doesn't compile. That's usually easy for experienced developers to sort out.

The ESP32 is natively running a customized version of FreeRTOS. The ESP-IDF documentation for the customized differences is very good. Besides the APIs and libraries made available in ESP-IDF, you can also directly call FreeRTOS functions for managing tasks, timing, and so on.

The bottom line is that I am using ESP-IDF in Eclipse CDT. So far, I have only been writing in C for this project. I haven't decided yet if I will later re-tool things into C++.