GAN's

I am agree with most of the people here, for learning colab is more than enough in the start (but you have to install libraries every time- keep in mind).

If you have basic knowledge of DL then it is better to go for desktop with gpu that you can afford (once install use always).

You can use kaggle as well for training your DL models. Others platforms you need to pay for it.

I will suggest you to start with Linux (it's totally UpTo you if you want to install dual boot or standalone). Most of computer vision libraries based on Linux and you can find more support for it.