I am going to be joining a pathfinder 2e game where I have been told the GM doesn't throw his punches. He will try to kill you. And that the difficulty will be souls like.
Got any advice on what to build or what things to focus on?
That sounds like not pulling his punches rather than not throwing them, but you might want to try the advice section of the forums rather than general chat. (You'll just get better results and more help there.)
- It's hard to argue with a Fighter's accuracy.
- Teamwork is important. Try to use at least one action to help out somebody else.