In My Humble Opinion - choice shows up when all of our habits and patterns and well-worn processes TRY to convince us to keep doing what we were doing before, but we end up doing something else.
For example - the chronic abuser of alcohol and cocaine finally hits bottom, has a moment of clarity, and realizes that if they keep on doing what they’ve been doing, and fooling themselves they will end up dead. They then go on to make a long, difficult effort to get sober, find a new group of people to hang out with, change their lifestyle, even though it is probably the hardest thing they’ve ever done.
The frustrated accountant who picked the job because it was the easiest thing to do, but now finds their work unsatisfying, who quits their job, goes to a culinary institute, busts their ass working in restaurant for 5 years, and nearly bankrupts themselves to open their own place, and finally finds satisfaction in becoming a chef.
The theoretical physicist who has this nagging feeling that the existing scientific frameworks do not explain some aspect of the universe correctly, who goes against the establishment and develops their own theoretical framework, which is first ridiculed, then re-examined, and then - perhaps only decades later - begins to be seen the right direction to look into, and becomes the jumping off point for other frameworks.
So yes, nothing is ever 100% choice or 100% determined - it’s a constant interplay within the two. But we humans continue to generate novelty - to combine things that were never before combined in nature and create new phenomena.