newb to arduino, how to navigate the ESP8266 vs ESP32 examples and tutorials?
Raspberry pi libraries and features are too wide to be covered in one answer. However, I can give you some pointers that helped me a lot.

Most of the programming will be done using Python. Most common libraries can be installed via PIP (the package management for python). You can access all sorts of things: image capture, GPIO, communication protocols and custom libraries.

Most often, you want to automate things on your Pi, two options can be used. You can set a python script as a service (example here) using systemd or you can use a Cronjob (sudo crontab -e) The service run at startup and can run continuously while a Cronjob is scheduled to happen at fixed time interval (example: reboot at midnight...). There are probably other ways to do automation and scheduling, but I found that those were easy enough to use without over-complicating things.

Keep in mind that a Raspberry pi is a different beast compared to the ESP series of micro controller. You get the full access and potential of a Linux platform with a slightly more limited interfacing potential(No readily available analog input/output is probably THE single frustration I had with the Pi). You can always interface another board via some serial protocol.

Regarding the other platforms, it's all about your intended usage. It's hard to point you toward a specific group of libraries. For my narrow usage of esp8266, Sparkfun Electronics tutorials were good enough. For Arduino, it is so widely supported that a simple google search willy yield you exactly what you want (there is also a stackexchange dedicated to that specific platform).

At the end of the day, most libraries are often quite similar and switching from one device to the other become more of a habit than anything else. I know that a lot of Arduino libraries are migrated to ESP platform so they even share common functions that are virtually the same in both platform.