Which is better, STM32 Nucleo or ESP32?

I am looking to make some projects like rover, drone etc. And after i get comfortable, i might try other types of iot projects and machine learning projects.

which mcu should i choose? i have already made some projects with arduino uno and esp8266, but some people have suggested to go with other dev boards. i did some research and it seems that stm32 nucleo is quite popular. but esp32 is also popular and has wifi and bluetooth, so i am kind of confused where to go next. i want good community support, modules availability and library support as i am a beginner and don't want to write libraries.

should i stay with arduino ecosystem ,or go with stm, or both?

I think STM32 Nucleo is the best because ESP32 has a low-power system
I mean you can choose ESP32 if you think to much power isn't that great!
(note: i am a newbie, so my opinions aren't as great as the other experienced users!)

Let me begin to say that both microcontrollers work at 32 bits (Arduino Uno works at 8 bits) and it is already a big improvement no matter which of the two you take;)
Even though the ST32 is a great microcontroller, if you are not going to use calculation and memory consuming programs I don't think you could notice a big difference between an Arduino.
My personal opinion is that the ST32 gives his best when programmed with CubeMx because it gives you the feeling that you are in real control of what the microcontroller do.
In the other hand the ESP32 has a quite huge fanbase and you can find plenty of tutorials on the internet, it gives you the possibility to use wifi and Bluetooth without an external module. Moreover, you can do an easy app with the MIT App inventor (really easy to use) and you can get a lot of support if you want to start writing some code on micro python.
In conclusion, I used both of them and since they are both quite affordable (both under 7$,if you take the blue pill for the ST32) I strongly suggest to take them both;P but if you just want to have one microcontroller around then I suggest you to take the ESP32 and have fun with IoT projects.
p.s. I forgot to mention that the ESP32 is dual-core

Nucleo is the best because ESP32 has a low-power system.