You could buy a Raspberry Pi. If you are okay with soldering, then a RPi 0W is probably what you want, and otherwise, a RPi 4. RPi works with Python, and electrical components (including motion sensors).
Dunno about RC Cars, but you can definitely make keyboards with a RPi, leading me to believe a game controller would be possible to make too.
You should probably buy the ELEGOO Arduino kit. You can choose either one but just note that they all may or may not have the same parts.
I mean, the Arduino UNO R3 isn't an official Arduino UNO, it's just a version that ELEGOO makes. So if you want an official Arduino UNO then you should buy one at arduino.cc.
You won't be able to use all the pieces in the kit but it's for fun anyways.
you should look into buying a car kit, eg: DFRobot Maqueen. it has servo motors, sensors, IR, distance, RGBLeds, etc.
exposed i2c port and three pins will allow you to start experimenting right away. it is supported by MicroBlocks as well. plus it forms a nice quality build that can be added on.