Oh wow, 2000 books! You have a huge digital library. Mind me asking, how much storage it takes up? Because I just started mine and have about 100 books and it’s already taken 2GB.
And you are right about using the iPad outdoors. The Kindle with its e-ink display is much better to read on when outdoors. This is one of the main reasons I wanted Apple to bring the Nano-texture glass display option from the iPad Pros to the Mini. They are just one step closer to turning the Mini into a dedicated e-reader. Until then, just like you, I will prefer reading on my Kindle when outdoors and on the Mini when indoors. At the end, what matters is that we are reading 📖