Woman professional Go players will answer your questions in turn.
question2
I mess up a lot of my games in the endgame. What kind of study should I do to improve at the endgame?

Consultation Two: by Mr.Taniguchi
answer
It’s very difficult to give advice on how to study the endgame. However, the good point about the endgame is that the problems are finite and one can find answers. I hope you become fond of the endgame.

As the first step, I advise you to study a book of endgame problems, as there is a lot of reading involved in the endgame. The next step is to play over the middle game and endgame in professional games.

One of the keys to getting strong at the endgame is learning how to calculate the value of endgame plays. Don’t just rely on your vague impression about the relative sizes of endgame moves; instead, please make an effort to calculate the exact numerical value.

Even so, some aspects of the endgame are quite profound, so working out the numerical values of moves is not always enough. However, you have to master the basics as the first step.

Just for reference, when I play through professional games myself, I calculate the value of endgame moves that come up. The endgame may be boring before you have learnt how to make these calculations, but it becomes an interesting puzzle when you can.
Consultation 01